While we're on the subject of add-on flight sim H/W, I also use some of the Saitek Pro Flight panels in addition to TrackIR. I've got a stack of 3 panels - switch panel, multi-function & radio. I can highly recommend these, but don't use the supplied Saitek drivers - they're rubbish. Insead, get the 'SPAD' drivers, available free from here :
Tools for Flight Simulator - Home of the SPAD - Home
Having real switches to click and knobs to turn saves all the fiddling around with key strokes and mouse clicks.
The radio and multi-function panels were immensely useful when I was training for the IMCR.