Re: I'm thinking of getting a ps3...
Get the 320 GB version of the PS3 and get a PS+ membership. You won't regret it. Considering you already have xbox live and a 360, I would recommend you really focus on the exclusives then choose the 3rd party games based on which console you prefer gaming on the most. I know I prefer shooters on the Xbox but fighters on the PS3, so it'll be up to you on third party games.
#JOY!Fact™: If you received all of the gifts in the song "The Twelve Days of Christmas," you would receive 364 gifts.