Again, that depends on your preferences. I think asking us who you can get is the wrong approach. It all depends on what the owners in your league are like. It's also part of the fantasy learning curve. You're going to make some boneheaded moves.
Hell, I remember when I started in 2003, I traded Johan Santana and Pat Burrell for some scrub like Phil Nevin. But, I learned from it, and so shall you, my friend.
So, my advice would be to check out your team, ID your weaknesses, and then see which owners you match up well with as a trade partner. Then, get to dealing! Trades are part of the fun of fantasy.
I never smile if I can help it.... Showing one's teeth is a submission signal in primates. When someone smiles at me, all I see is a chimpanzee begging for its life.