I'm curious about the monitor controller situation myself. I just bought a Lynx Aurora 16 (for a number of reasons - good experience with them in the past and of a number of folks I know personally who use them and love them, as well as the best channel-count-per-cost while still being good quality). I got Firewire. I've been using Firewire for a while so I know it's stable with my system, works great with my setup.
Anyway, I've been doing a bunch of research on monitor controllers since I need one now too. After everything I've read right now I'm between the SM Pro Audio M-Patch 2 and the Radial MC3. Right now it doesn't make sense for me to spend over a grand on this, so I'm going with one of these for now. Either of them is good for me feature-wise - the headphone out (or two outs on the Radial) would free up my current headphone amp to be used just for clients, so that'd be nice. Curious to see what other folks say/use.