Was at first interested in Silent Storm, but then the
fantasy space-suit armours with machineguns for hands turned me off completely...
Personally I loved Brigade E5 (with obligatory Badass or Blood Money mod or both, dun remember anymore), and its sequel
7,62 High Calibre (with obligatory Blue Sun mod).
I on the other hand, would love to see a UFO game utilise that engine, the realistic looking guys (cartoonish design always irritates me), destructible stuff, a zillion available weapons, time speed control and a decent realtime pause system.
Could do without the many random crashes and bugs though...