Yes, because it would be another important sale in the console war. Doubt it's worth it to you personally though.

You Shouldn't not buy a 360.

I had a PS3 first for a while then eventually got a 360. What tipped the scales for me was:

a) reached around 7 exclusives on 360 I wanted to play. If there had been less than 7 I would have been pretty hesitant

b) a lot of my kid's friends used 360 so I knew they (but not I) would use cross-game chat and party chat a lot. Otherwise I would have been hesitant to pay for Live. Not that Live is expensive (from my perspective) but apart from a slightly better in-game interface and the cross-game/party chat it is the same as PSN. Actually playing games like CoD, etc. I never found any difference in quality , speed, etc. On the same network they were the same.

c) I live in UK and getting a 360 enabled me to put it in another room and use it as a third Sky Box for TV/Movies.

Kinect I have to say I've found worse than Move and Wii. It is very good for dance/fitness but worse (technically) for pretty much everything else I've played. Tennis, shooters, etc. are all better with Move/Wii. I know it's popular but don't confuse that with actually having great games. TBH if you want motion control games Wii is still miles ahead of either PS3/360 in terms of number of quality titles. Most Kinect/Move titles are terrible and oveall, apart from party stuff with groups, they don't have much to recommend them unless you use Move with Killzone, etc. where Move is good. Right now in terms of hybrid games Move is actually ahead of Kinect for titles.

So I'd say be sure you're going to get your money's worth. Most titles today the different between 360/PS3 is minimal to zero. Only a few well known developers still produce inferior PS3 versions. And TBH unless you know your stuff you actually won't be able to tell the difference. Apart from a few glaring exceptions to the average gamer/eye the titles look the same.

Conversely, if you do want eye candy the PS3 remains ahead in terms of exclusives due to its own development houses. The 360 gets very few games with custom engines, practically none in terms of overall library, compared to Killlzone, Uncharted, God of War, etc. all running on custom engines. Really today the situation is 360 and PS3 have most games looking the same, the 360 has a slightly greater number of multi-platform games looking better than PS3 and PS3 has the best looking exclusives, so it all tends to cancel out in the end,

The 360 is a good console for sure but in truth it's 90% the same console as the PS3 in terms of features/library at this point, perhaps more than 90% the same even.

So be sure it makes sense money/use wise before commuting to one would be my advice - for example by switching to Live for all online (apart from exclusives like Killzone).

I say save your time and money and place it elsewhere.

Don't waste your money on a 360 if you're buying it for Live. It can be better than PSN but not hundreds of dollars better. Also don't waste your money on Kinect. It can be fun but again not worth its price. I have all three systems and game on my PS3 just like you, except for exclusives.

If you want a 360, buy it for the games!

Funny. I was just reading my latest issue of GameInformer and they reviewed Forza 4 (a 9.25 I think) which is a great score. On the side bar they did a quick review of Forza with Kinect and they said it was absolutely horrible. The arm driving was absolutely lackluster, the head tracking completely pointless and horribly implemented, and an overall massive failure. Does your friend like it just because he can use Kinect? Or does he like it because it actually adds to the game? I think we all know the answer to that. As for the OP. If you have a PS3 already AND seem to enjoy PS exclusives... Why would you get a 360? The two are so similar. Rather than spend a lot of money on a new system/games you should upgrade to a 3D TV for your PS3. Trust me, you won't regret it. Sure it doesn't add to games, but it is quite an amazing experience if you haven't tried it yet. Plus, many games that you wouldn't expect support 3D and are a blast to play in 3D. The PS3 just does more. My fiance and I use it for Hulu Plus (Which the 360 recently got) she uses the Web Browser for Facebook Mobile which runs super smooth and super fast, we have over 100 downloaded movies packed into the video sectioned in alphabetical order and it looks sweet. Tons of pictures and music. The PS Store does everything Live does. People don't seem to understand how similar the two services are, except 1 you have to pay for. Unless you have 20 friends you plan to play with frequently, stick with your PS3. Or get a Wii. PS3/Wii or 360/Wii is the better combo to get a more wide varienty of games. PS/360 are just too similar to justify purchasing both. A lot of multi plats recently are exactly similar to the 360 or better (according to DF). Stick with what you got this late in the generation. 

the fable series,condemned criminal origins,pgr series are very good racing games,halo series is such a great fps,left for dead series is very good.
kinect is so awesome and your gf will love it and play it so much, also i enjoy playing kinect so much i cant wait for the 2012 games even more to experience those what they have too bring to the table.
xbl and psn are close enough to not be that much of a factor, but if u or your gf like the idea of using a avatar and getting clothes and objects for them to show off and do the cross game chat with your friends when u play games. are worth the experience of the 360/kinect.

@bolded - I am the one who played Forza 4 at a friend's place and thought it was great. I'm not really much into reviews especialy those that include Kinect just because very few of those reviewers are fair. Kinect games can be really fun as long as you're not one of those who think you look stupid while playing. It's incredible how "stupid" we can look while doing things in life yet nobody thinks we should stop living.

Sometimes I am glad I don't restrict myself from doing or buying things just because of some false beliefs I have. Except for money, people shouldn't restrick themselves from having fun. You look more stupid when you try to attack someone's choice of gaming than those who dance alone in their basements... (I'm not directing this at you Raider84). 

To the OP, if you can't justify your purchase then don't make that purchase. If on the other hand you think you and your girlfriend could benefit from the 360 then why ask people about it? They're not the ones having fun with the console. Some will try to convince you to buy it while others will try to convince you you're making a mistake but are they in your situation? That's always a question I ask myself, those who I ask to, are they blind lovers, raging haters, are they in the same financial situation, do they know what they're talking about and so on...

Kinect should really not be the deciding point to buy a 360, I'll tell ya that. Aside from Dance Central 2, there isn't much to see for your gf.

You sir are wise beyond your years, thanks for the advice! Very impartial and deep.