Hi All! I'm looking to upgrade from a 12" combo to a separate head/cab setup. Genres of interest include jazz, blues, rock ('60s & '70s), country, and - occasionally - reggae and bluegrass. A wide variety, I know. I've never done any gigging (I'm still learning), but the 12" combo just doesn't have the "presence" that my ears are searching for. I get together with a few friends from time to time (drums, keyboard, guitars) and I really have to push the little combo unit to keep from getting lost in the mix. So I figure it's time to move up. I want something simple & lightweight, yet powerful enough to keep me satisfied as I grow & learn without having to upgrade again for a long time. (That's assuming, of course, I wont be "discovered," then invited to play at the next blues or jazz festival and suddenly need a 2000 watt head pushing a couple of 8x10's! ) I'm thinking a head capable of 500 - 1,000 watts at 4 ohms would be perfect. But I've also got a wife, two kids and a mortgage, so I can't go all out. I haven't decided on a cabinet yet, but the idea of a 2x12 (vertically stacked) seems to make sense to me. Small enough footprint to be manageable at home, but still able to move a lot of air, if I want to take it out. Having said all that... Which of the following two heads would YOU choose, and why? Genz Benz Shuttle 9.0 -OR- Genz Benz STM-600 Streamliner Other recommendations are appreciated, but please answer the question first. Thanks in advance for your input!