Look at the gear the guys that influence you use. Most rock acts use Ampeg, Ashdown, Mesa, GK, etc. Even if its not what you actually hear its still an indicator of the sound they like. Have a look at the endorsee pages and signature models on the amp makers website can give you an indication. Go all valve if you have the dosh. The Gallery site is a good place to start as they have links to all the makers sites.