1. The x51v has great 3d graphics, probably the best of pdas on maket today. Trust me, the x51v has 640x480 vga display making it a gamer.
(Example of Acky's XP Breakout in VGA)
2. Quite a few windows games are also on the ppc. I dont know what happens to non open source games though.
3. Just look for games that are vga and windows mobile 5 compatible. That way youll have the best games for both the os and the graphics.
4. There is a playstation 1 emulator for pocket pcs. Get it
here. Many people like to emulate snes games on the ppc, b/c smaller roms, and faster on older pdas/etc.
Welcome to Aximsite, I am not your vga person, b/c i own a qvga, but there are many others here...