When? because in a few months, there will be haze, Drake fourtune, heavenly sword, Lair, home and other excclusives apart from Rofm, motorsport, war hawk and other great PSN games. Also, you need to get some of the PS2 classics like Shadow of a colossus, God of war, MGS and others.
If your brother's the one footing the bill, then I'd go for it ;) Seriously, there are quite a few really good games out at the moment, (Resistance: FoM, Rainbow 6, Motorstorm), as well as some on the store, (most notably Tekken DR and Warhawk) and apparently some real entertaining ones due out in the runup to Xmas. (Including, but not limited to, the online patch for Tekken, Home, Gran Turismo, Smackdown 2008 (I hope), Stranglehold, and plenty of titles I'm sure I'm forgetting).