As far as my top ten goes, I find it neccessary to include this/these caveat. I base my top ten on probability + ceiling + impact and that's in order of importance too me. I don't care how high a guys ceiling is if he has question marks surrounding him that make his probability of making it to and staying at the big league level minimal. IMO that's not a prospect it's a suspect. The further away from the bigs the less likely they are to make it. That IMO is why we have so many arguments about prospects list we all have different criteria about what a prospect is.
That said here's mine off the top of my head.
1.) Thompson
2.) Frazier
3.) Valaika
4.) Wood
5.) Alonso
6.) Roenicke
7.) Stubbs
8.) Mesoraco
9.) Maloney
10.) Rosales
If I were ranking it strictly on star power this list could be it although I don't know about the order after Thompson it's somewhat interchangeable.
1.) Frazier
2.) Alonso
3.) Thompson
4.) Mesoraco
5.) Stubbs
6.) Wood
7.) Valaika
8.) Roenicke
9.) Soto
10.) Lotzkar