PSP for me.
It was my "smartphone" until like 2010. Maybe even longer.
-Great games. Felt almost like having a PS2 in my pocket.
-First time I went full digital.
-pictures, music, movies, browser, wallpapers, online play, emulators,
The PSP was a beast. The DS was a toy. A really fun toy with some classics and some innovative ideas but not on the same level as a PSP. I've been playing portables since the original Gameboy but I don't think I've ever enjoyed one more than PSP, even now.
Best handheld, ever.