I'd like the DS lineup -- well, three titles in it (Castlevania, Mario Bros, and Mario/Luigi 2) -- but with PSP sound/visuals instead of abhorrent low-rez, stylus-distressed design. The rest of it is largely rot.
That said, I've never trumpeted the PSP's current short-term lineup -- it's also largely rot, GTA, GGXX, and Burnout Legends excluded. Hopefully some of those action RPGs and strategy RPGs from Konami and NI pan out, although I'm not crossing my fingers. The Tenchi no Mon demo was fun, if a little shallow, and it sure as hell looks a sight better than anything on the DS.
Also, wasn't Katamari announced for the PSP? Was it ever -really- announced for the DS? Not that I really care since I could never get into the original, but I seem to remember Namco dropping the DS version off of its homepage. Another game made impossible by the DS' ancient hardware, I suspect.