This is going to get as many subjective answers as "Who's the best guitarist?"

I prefer Dean Markley Blue Steel. They give me the *impression* that the strings are very crisp and clean, and I am a freak about changing my strings every day when recording. I've always wanted to do an A/B test, though.

I've heard a lot of good things about Elixer.

You should definitely try out different brands and see if you can sense a difference. It could help develop your ear / sensitivity for tone.

-Carl.