I've noticed here and there on various message boards the idea of "compromise systems". You often see this in the vein of "Well, the group wanted to try Rolemaster, I wanted to try Savage Worlds, and we settled on d6" (ok, maybe not that particular group of games, but you get the idea).
I've had this in gaming groups, too. We talk about a number of different systems, but then end up playing something familiar. For a lot of groups, this means some version of Dungeons & Dragons, since it is the lingua franca of the hobby. This isn't necessarily a bad thing--at worst, it does possibly deny folks the opportunity to play a new system they might like, but if there's a middle ground everyone is comfortable with , that's not a bad option. Plus, time constraints and good old-fashined bullheadedness might make learning a new system a chore, if not an outright pain.
If you've got the time, of course, a demo or one-shot might be the best way to see if the group is going to dig a system. Financial outlay (if a system doesn't have a "lite" or quick-start version) can be a consideration against this.
There's also setting compromises. George has a hankering for Eberron, Edgar digs Dragonlance. Maybe we play in a mishmash of the two--enough to offend any setting purist, but perhaps enough to give those two a fix of what they like about those settings. Then again, maybe we all play in Forgotten Realms as we have the last 3 campaigns.
I think the thing to remember is that if you've been running a game and the players talk about wanting something else--it isn't an insult--we all want to try something new. For many groups, a moderate approach of seeing if you can add some of what's wanted into your game without making radical changes may be the best way to avoid alienation. Then again, listening and responding appropriately to your group is always the best way to avoid alienation, but that's a given (or should be).
Do you or your group have a "compromise system"?