Actually, everyone should play all the 2D Metroids.  As Sakamoto has said there's going to be story connections to all the games in there.  That pretty much means Metroid: Zero Mission, Metroid II: Return of Samus, Super Metroid and Metroid Fusion.

And just because all the 2D Metroid games are awesome.  Especially the overlooked Metroid II on GB (which has some of the biggest connections to the overall Metroid storyline).

Edit: As a note, I went back and played Metroid: Zero Mission, Metroid II and Super Metroid just last week and it only took me about 5 hours total for all 3 games.  So its not like its going to be a mjaor drain out of peoples lives.  Though I did set a personal best time for Zero Mission and even got a time of 1:20 on Metroid II while not even trying to rush......  But that's not the point!  The point is, you can play the games pretty quick.

Playing all the old Metroids would be good but Super Metroid is especially important becuase *Other M starts off with a flashback to the end of Super Metroid.

*slight spoiler highlight to read

So Prime has nothing to do with Other M? Even if it doesn't should I still buy it? Also I do have Super Metroid because you people told me to now I am stuck already so...

How do you use the morph ball in Super Metroid?

You push down down (I think) and you use it to go through narrow passages.

Here is the Metroid Timeline.

Metroid  and Metroid: Zero Mission (NES and GBA)
Metroid Prime (GCN)
Metroid Prime Hunters (DS)
Metroid Prime 2: Echoes (GCN)
Metroid Prime 3: Corruption (Wii)
Metroid II: Return of Samus (GB)
Super Metroid (SNES)
Metroid: Other M (Wii)
Metroid Fusion (GBA)

I was in the same boat. I'm not a hardcore gamer and I haven't finished a Zelda since OoT even though I have all but 4 swords.

Having only tried Prime 1 & 3 I felt I owed it to myself to give the series a proper chance. So last summer I picked up the Trilogy but never played it until a couple of weeks ago and the only thing I'm sorry for is not playing it sooner.

After you overcome getting around (i just got good at using the in game map) the game isn't all that difficult. So if you have the means I recommend you get it.

if you found MP3 too hard for you then mp trilogy is not for you. while they are 3 incredible games, both mp1 and mp2 are harder and more complicated than mp3. in fact for me mp3 was a disappointment because it was too easy and linear.

but you shouldn't worry for metroid other m... that game will have almost no correlation to the prime trilogy, both gameplay-wise and story-wise.

Try to use the scanner everywhere to familiarize yourself with discovering the hidden routes.
You should get better at recognizing where to go next the more you're into the game.
And learn to use the 3D map. Especially useful if you get lost in the 3D world easily.

" I have played about 4 Zelda games and have never even come close to beating one."

errr....really? try phantom hourglass, the controls are simplified so the gameplay is in itself simplified a bit too, yet it's still very enjoyable.

Try NSMBWii, there is a feature to help you in the game. Moreover, it seems most future Nintendo games will have this feature, so be excited for that!

What got you stuck in MP3? Was it the enemies? Did you get lost?

I just don't know how to use anything like the map or the scanner thing... The 1st time I played I got to the 2nd area and didn't know how to use the grapple chain thing and I read the manual and I still couldn't do it.(I know its sad) I had to send my Wii back to Nintendo and it got erased so I tried again and now can't even get th the part I was at before... I got lost.