After playing a shitload, here are my thoughts:

-- Restarting a previous world is cool for that little test server, but we shouldn't do it for the main server if we go modded -- too much hassle to go far enough out to get the stuff you need to be generated and too much temptation to cheat otherwise.
-- Use all of Red Power. Lighting and transport are cool packages that add stuff without the bizarre matter-generating stuff in IC2. Eloraam is also testing out Frames which is pretty wild to see.
-- Drop Forestry mod.
-- Consider dropping IC2. I'm not really in love with it, and I know a lot of people have problems with the "something-for-nothing" matter generation. I dunno, its cool but its way outshined by BC and RP.
-- If you do go with IC2,
---- Use a power conversion mod -- there are a few out there. Power crystals (I think was his name) wrote one that allowed you to (fairly) convert BC power to IC2 power and vice versa.
---- Make sure the ores are all correctly setup on the config options of the various packages (they aren't currently)

I'd be willing to test out other mods, but my $0.02 on the mods I've tested so far:
-- Red Power2: Yes, all
-- IC2: No, but wouldn't really bother me
-- Forestry: No, but wouldn't really bother me
-- Equivalent Exchange: No, spirals out of control quickly
-- BuildCraft: Sure

I also think the "portable crafting table" mod where you can upgrade your 2x2 personal crafting area to a 3x3 one would be pretty boss (just saves you from having to lug around and setup a crafting table) as well as a larger inventory / backpack mod.

Anway, just by 2c -- If you haven't checked out the server, talk to acid.

Heres the power converter video:

(SMP compatible)