Here is what I have done in multiple vehicles..
Buy a 4 channel amp that is 2 ohm stero stable.
Hook up all 4 6 1/2s to the front two channels, and then bridge the rear channel for your 12" sub. THough, if you desire the fade control capability on all speakers, then this would not be your best option.
If you want full control, then like whats been said, a 5 or 6 channel amp would be key, and since your have plenty of outputs then your good to go.
On brand.. well, sometimes the best isn't the best. Some "higher" end brands now focus on advertising and appearance, other than quality *cough*Kicker, JL Audio, Rockford Fosgate*cough*
Make sure that the amp you do buy, you are able to handle and look at in person at a store front in a local store, and make sure you get a good warranty. Circuit City and Best Buy have good warranty programs. Local shops usually do to. And for example, I have had my Profile California 50X4 amp for 6 years now. Still works fine and never gave me issues. It was always hooked up right. So the install has to be correct. Make sure your wire guage is proper, and yes, a nice capacitor and maybe a deep cell barrety will allow you to have full potential of your amp. And since you said its going in a 'Vette, I would buy what it takes to make everything proper.
I myself am looking at buying a DBdrive Speed series a490 amp. It has:
4 X 90 Watts @ 4 Ohms
4 x 180 Watts @ 2 Ohms
2 x 360 Watts @ 4 Ohms
· Class "AB" Circuitry
· Audiophile Grade Components
· DRIVESINK Technology (Heat Mgt. System)
· High Efficiency Mosfet X Outputs
· On-board High/Low Pass X-Over
· On-board Bass Boost Remote
· Enhanced Dynamic Performance
· 2 ohms Stereo Capability
· Bridgeable
It runs about $250, but its worth it with a 2 year warranty
THough, I never care about hooking up multiple amps. I have a 4 channel amp and a mono amp in my car. Took about 3 hours, but there is alot of wires. Oh well...