A DS or a PS3?

I haven't bought a DS before now because I either didn't have money for it or it didn't entice me enough, but sometime this year the sequel to one of my favorite games is supposedly going to come out for it. However, I'm hesitant to buy a system thats 6 years old and due for replacement soon. On the other hand, because it's so old, there are a lot of games for it I would like to play.

I technically have enough money for a PS3 right now, but given all thats going on in my life I really shouldn't spend... well, actually, I really shouldn't spend any of it. But the sequel to my second favorite game is going to come out for it sometime soon and there's already a few games out that I would like to try, it's current, and I'm wondering if it wouldn't be a better long term investment.

What do you guys think?

What are your favorite games and your favorite game genres? Specifics will help.

One consideration: if you're not averse to emulation, the DS can already be emulated pretty decently whereas the PS3 likely won't be for many years (and certainly not with modern CPUs.)

What would you use more? I think you could get more use out of the PS3. And theres always the ability to emulate the DS.

PS3 if you are going to be home, if you travel a lot the DS is very useful though.