well your mic is the begining of your chain...so put some time into finding out whta mic you want...
go test them out at Guitar Center, it might be the perfect mic for someone else, and the worst for you,...
Monitors are important for mixxing, but point blank, if your room has bad acoustics good monitors almost go to waste...i wou ldn't worry about getting great monitors, i mix on headphones and monitors(not great ones) and my mixxing isn't bad at all...
just my opinion