I think it depends a lot on your gaming interests:
The PSP doesn't do it for me, for the games do not appeal to my interests.
However, the PSP DOES have better graphics and there are a lot of interesting exclusives (dgsige named a few: but you forgot the new Silent Hill
) In my opinion, the PSP is more based on larger adventures and bigger worlds, thus long-play.
As for the DS, because of its popularity, there are a lot of crappy games beingreleased, just like there were a lot of crappy games on the PS2 when it was at the top of its popularity. However, the GOOD games (what 'good' means in this sentence is up to you: in my opinion Mario, Zelda, Meteos, Age of Empires etc.) are fun to play when you're traveling. Some of those tiny mini-game type games are also fun to play. Also, games like the new Contra kick ass
The most use-able option of the DS is that you can put it on 'stand-by': just close it, and it will stand-by for about 120 hours. When you open it, you can continue playing (however, I recommend saving everytime you do this: just in case. When I was playing Age of Empires, the game froze after putting it on stand-by).
Lately, I bought a MP3-player for my DS. Have the best of two world, I'd say
I conclude: the DS is more suitable for me because I travel a lot.
It's good that Sony is trying to expand their influence to the portable console market: it makes that market, dominated by Nintendo, a lot more interesting! In this year, people are gaming more then ever, even if it's on a Wii, DS, XBOX360, PS3, PSP or whatever! Me like!
_________________
---------------------------
When you're this cool...
They're out to get you...
- The Fonz -