Bicycle Mechanics - Shimano and Campy

I am upgrading my components. I have all Shimano right now. My question is, will Ergo shifters work with Shimano Brakes and Derailleurs?

brakes, yes. derailleurs, technically yes. cassette, no. the cog spacing is different so the shifters will pull a different amount of cable per shift.

so in other words this will not work?

You will need to get a respacing kit from Wheels Mfg. to respace the cassette to work properly. It is a relatively inexpensive way to get Campy quality shifting on a Shimano equipped bike. I have a 9 year old Campy Mirage grouppo on my bike, mated to Spinergy Xaero-X wheels. Since Campy 8 speed compatible wheels are hard to find, I went with a Shimano compatible hub, along with a SRAM cassette and chain and a Wheels Mfg. kit. I was out today (it hit over 50 here in Boston), and it shifts like a freakin' dream.

You can use ERGO 10 levers with Shimano 9 derailleurs with a very simple cable adjustment- but the shifting feel isn't quite as nice.

Campy levers will work with Shimano brake calipers. Campy calipers won't work with Shimano levers (the reason is that Campy has it's brake open on the lever, while Shimano has it on the caliper. Use a Campy caliper and Shimano levers, you will have no way to open the caliper for adjustment or to pull out a wheel.)
For simplicity's sake, I would just keep it pure.

I am upgrading my components. I have all Shimano right now. My question is, will Ergo shifters work with Shimano Brakes and Derailleurs?

You cannot mix a Campagnolo shifter with a Shimano derailleur or vice versa and get good precise shifting, but the spacing on both brands of cassettes is close enough where you can use a Shimano cassette with an all Campy drivetrain or a Campy cassette with an otherwise all Shimano drivetrain. This only applies to 9 speed.
A spacer kit will only work on low end cassettes that do not use carriers which combine 2 or 3 cogs permanently.

flakey-

That's why I used a SRAM cassette. No spiders to worry about, just 3 small hex screws holding the whole works together.

You can use ergo10 levers with Shimano 9 derailleurs and brakes (you cannot use Shimano 9 STI with Campy derailleurs).
It takes a minor cable adjustment and the feel isn't as solid as Campy nor as seamless as Shimano but it will shift with no problems with no need for spacers or different cassettes.

There are no other accessories or modifications associated with doing this.