What type of electric guitar amp to get?

Right now I have an rg 321(horrible pickups, going to change them, this guitar is for metal so most likely emgs because it is a bolt on), a 60's style fender strat with SRV pickups, and a Jackson Dk2 dinky with sustaniac. I am going to eventually save up and buy some sort of Parker guitar with the Piezo system. However, first I need to upgrade from my marshall 100hdfx halfstack. I really like Joe satriani's tone, but also love vai, petrucci, and paul gilbert's tone. I basically want something that can give me a screaming lead tone, a super crunchy rhythm, and if i wanted to go a little heavier a decent drop tuned (drop a#) tone. The drop tuning is not what i am looking for, but i do want an amp that wont sound completely terrible if I use my rg. I do not really want an orange or a marshall, the british sound is too common and I am tired of it. I heard Mesa Boogie would be great for me, but also somebody mentioned possibly Carvin. I really have no idea what would be best. Please enlighten me, I do have a price range but will not mention it because I am considering saving up for a while; I do not want to have to upgrade from this amp for a long time.