Xenoblade without a doubt. I played both, and Xenoblade is better in almost every aspect than Last Story.
Also, Xenoblade offers a lengthy story over 80hrs, while I beat The Last Story in 20hrs.

Xenoblade, because it'll take you a month or two to finish it. By then The Last Story will have had many a price cut.

Both are worth buying, I gave you the cheapest option.

I haven't played The Last Story, but I can tell you that Xenoblade is the type of game that you will log over 100 hours on so I can definitely tell you that it's a good bargain.

The last story has got a better graphic, better characters and better story (it's just my opinion, of course) but it's a bit linear while Xenoblade Chronicles is a bit more open world.

i own xenoblade, and preordered last story, but unfortunately have yet to play either due to starhawk's multiplayer consuming all my little free time. Gonna unhook the ps3 soon to make myself play the last story, before taking on the huge investment of time that will be xenoblade. Anyway, i've done quite a bit of research on both and i will say this; the 2 things that the last story have over xenoblade are the graphics and the soundtrack. Xenoblade looks good, but from what i've seen, the last story looks better. The soundtrack is written by Nobue Uematsu, who happens to be my all time favorite game composer and one of my all time favorite composers in general. He wrote the music to final fantasy(s) 1-9 and parts of 10. I got the pre-order for the sole purpose of getting the included soundtrack. The battle system in TLS seems to be more up my ally, but the depth of the skill tree in xenoblade seems to be without equal. The best advice probably came earlier when a post said to get xenoblade and by the time you beat it TLS will have had a price cut. On the other hand the publisher of the last story (Xseed) said they were only planning on making one batch of copies of the last story. Still, i'm willing to bet you will be able to find it used for pretty cheap in about six months after launch (probably in the 30-35$ range).

why must ppl choose between one or the other?? buy both

Read the OP.

Xenoblade. ...but i'll warn you, i haven't played either. i just like voting.

Pick whichever one has music you enjoy more.

The Last Story may be prettier, but it has a lot of cons compared to Xenoblade.

It's really short for a JRPG, and the battle system is awkward.