DS is a great little sytem. Got one at JPN launch, then went on to get 2 DS Lites.
However, after a while I realised the games were not cutting it, and I went for a PSP.
Never looked back. I only need one portable, and the PSP is the one for me. Will have a 3000 in a little over a week.
8GB memory stick and a ruck load of PSX / PS1 games from the Japanese PSN has me well contented. Some top stuff on UMD too.
Whatever floats your boat.
PSN - hanafuda