Currently a sluggish/PITA iOS4 on a 3G iPhone. I'm torturing myself using it while I wait to see how Microsoft's WP7 release next week and in the weeks afterward is received. I don't like the initial limitations being placed on the WP7 by Microsoft, but I'm still leaning towards an Android or WP7-based phone as my next phone.
currently, i have every iphone that's ever been out and i recently picked up the tmobile G2 android phone. i can say that android > apple. i can download files off of newgroups, unzip them and play the file, all in my hand. customization is 100 times easier, looks nice and you dont have to jump through hoops to get the theme/icon setup you want. all the games you want on the iphone are on android and it's easier to bootleg too (not that you should. you shouldnt, that's illegal ) and playing ff7 or any psx/snes/genesis/etc on the G2 runs smooth with a physical keyboard. the phone is like a handheld computer.