As for best Trek game, even though I haven't finished it, would have to be Star Trek 25th Anniversary. It was a point and click adventure game set in the TOS period (I like to think it's year 4) and was fully voiced by the entire original cast. It's great, you get to actually fly Enterprise and go anywhere you want in the galaxy.
Runner up would be the Star Trek screensaver set by After Dark. Oh the hours I frittered away playing with those. My favorite two were watching the Horta burrow tunnels all over the screen and occasionally kill a red shirt and then having Spock wander around my desktop. The bridge one was awesome too.
Absolutely. When my family got our first Windows computer (1993 IIRC), "25th Anniversary" and that After Dark screen saver were all I'd ever do on it. That and "Where In the World is Carmen San Diego," haha. The sequel game "Judgement Rights" was just as cool. Having the entire cast of TOS reprise their roles was worth the price of admission.
If TAS is the fourth year of the five-year-mission, "25 Anniversary" and "Judgement Rights"is the fifth! Or maybe it should be the other way around considering all the changes in TAS (Arex, M'Ress, two turbolifts on the bridge, etc.).