For strings, it is kindof a personal preference thing. Personally, I use number 10 Blue Steel strings on my strat. They sound great and last pretty long.
I have also used Ernie Balls, and D'Addarios on my strat. I like 10s because i get a good ballance of lows mids and highs, I play blues, and classic rock and rock.
I suggest getting some signle packs of a few different kind and guage and try em out till you find some that fit your style and sound.
Have fun!wwww