Can anyone advise as to how many outlets I can put on a single circuit? I don't know what, if anything, the code says on this, but I've spent about an hour looking at it and can't find anything in the way of limitations. I want to put about 8-12 outlets on a 20 amp circuit, using 12-2 wire. The receptacles will be used in the living room and bedrooms (not bathroom or kitchen) - night lights, TV, radio, vacuum. Any problems with that? Would I be better served by splitting up the receptacles with 2 circuits? Is there a rule of thumb I should follow in terms of the number of outlets on a single 20 amp circuit?

Do you generally set up a dedicated circuit for a microwave? The local code says I only need one dedicated circuit for the fridge and 2 20 amp circuits in kitchen for use with small appliances. I am wondering whether its best to set up a dedicated circuit for the microwave, which, if I remember correctly, will draw close to 10 amps.

I think 8-12 outlets is little too much for one 20 amp circuit I would say do 5-6 max but that's my opinion and what the books I have read say. Downside of having too many is you trip breakers more often. Also, don't see why you need a dedicated outlet for the microwave when you have 2 separate 20 Amp circuits at the kitchen counter. But hey if you really want a dedicated circuit than go for it.

There is NO code limit to number of receptacles on a circuit. IMO 8-12 is typical for a general use 20A circuit.
The only reason to go less is if you know specifically what each one will be used for. In a BR or LR chances are most of them will not see any use beyond a table lamp or alarm clock.

Oh, the microwave issue. If the micro is in a dedicated space or fixed in place it must have it's own receptacle. If it is just sitting out on the counter you can power it from one of the two small appliance circuits.