I have been playing bass for about 13 years and started out with a little 40w combo and as soon as I could afford it, I bought a monster rig. Then when I got older I sunk about $5000. into a killer rig consisting of Hartke power and Eden cabs. I got out of music for a while and sold it all. Now that I am coming back into it, a fellow bass player mentioned that his rig consists of an Ampeg pre-amp and a PA power amp. Instead of the pre and post combined in one unit, he seperated them. He says it gives him flexability in that he has a few different power amps and he can choose one based on the venue...I told him that my rig is flexable as well, it has a VOLUME knob. Has anyone else used a set up like this or know anyone who does?? Before I start sinking money into another set up, I sort of want to explore all my options.

Also looking at Tube vs Solid state....
To be honest, I think that a seperate PA/pre-amp setup woudl be really cool, but meh, I don't really think you do need a traditional pre-amp. I would just use regular effects and a booster at the end., but I may be wrong in doing so.

Also, you may notice that there are different types of pre-amps. Some for Bass, some for Guitar, and some for Live Setups. In my opinion, it doesn't really matter what PA you get, since it really doesn't matter that much (I only recomend profesinal PA setups becuase you can't really beat 3-5000Ws of pure power, now can you? )

But remember that whatever setup you get, get Bass speakers! Or else you will you go through Cabnets more than you go through sets!
You can also put power modules into cabs as I do, for preamps I use either Ashdown or Bass Pod XT Pro, as you say more flexibility.
G&L L2500
Squier Affinity Jazz Bass 5
Ashdown RPM pre-amp
Ashdown Little Giant 1000
300 watt 15" powered cab
450 watt 15" powered sub bass cab
2x10 + horn
1x15x10 + horn