Received large online "GIFT". What game is most profitable to play?

I'm fortunate enough to know someone that won a large sum of money recently (nothing to do with poker). This person knows I love online poker so she gave me 5K to play with and we'll share the winnings and she told me "if you lose, don't worry about it. It's just a fun gamble". I have not deposited the money yet, and I only play Pokerstars so I need help to point me in the right direction to my best interest.

Obviously this is a great predicament to be in. I'm wondering what is the best site(s) for me to play on, taking into account bonuses, and strength of players.

A little about myself. I have been playing online poker for about a year. I consider myself an average player. Sometimes I do lousy in $6 SNG's and sometimes I win $200 SNG's, just like the average run of the mill player. I often play $10-$150 MTT's on Pokerstars and have done well, but never won a tourney. I have made 10 final tables but have yet to get my first win. I'm average at Ring Games. I like to play $5-$10.

I know a lot of this is pretty vague, but its all the info I really have. If anyone could tell me what my best bet is, as far as sites, and the games I should play to make a profit I'd appreciate it.