From what I've read of Homefront, which is similar to what MARKakaJIM has said on previous page, the multiplayer saves a somewhat lackluster singleplayer, so depends what you prefer. With MP FPS games though most people seem to fall back to COD within a couple months so can't tell how long it's MP will stay populated.
As for other suggestions, Bulletstorm is supposed to be a very slick and fun singleplayer game. Though from what i've seen it hasn't impressed me personally but everyone else seems to rate it currently. Crysis 2 has been receiving high praise and also looks amazing, could be worth checking out. Mass Effect 2 if your into RPG's as it was only recently released on PS3. For racing, Need for Speed shift 2 is released Friday and is looking much better than the first.
If you don't mind waiting a couple weeks, portal 2 is released 22nd April and if you buy it on PS3 you get the PC version free. Worth keeping an eye on atleast.
On another note, for fans of the Call of Duty type games. Battlefield 3 is aiming to take COD's crown at the end of the year. Heres the first of their "Fault Line" trailer's for those that haven't seen it elsewhere.
http://www.youtube.com/watch?v=uA378g_gD1I