ha, took it right out of my mouth seriously though, X-Com (or UFO, w/e) has got to be the best TB-game and one of the best games of all time, JA2 is small time compared to this mammoth)
Not to take anything away from Xcom, but I'd put JA2 above it in regards to the actual TB combat. Of course, it came out much later and was refined after JA1 and Deadly Games, but it is still the king of TB squad tactical combat.
Xcom trumps JA2 by having an awesome strategic layer though, with research, base building, and all those other brilliant layers.
Speaking of JA2, unlike Gorth I have a small flicker of hope deep inside that Bitcomposer will turn out a decent remake of JA2.
edit: Dang, just read that plan and go thread. My flicker just dimmed considerably.