I'd say Frostfire's "Here Is no Water" (http://frostfire.killerstar.net/stories/nowater.html) would be a good choice - it seemed to spark a Mitchell/Sheppard crossover trend.

I'd also list your "Last Port of Call" as a well-writen story that caused a lot of spirited discussion in fandom, though I can understand you might be reluctant to include it for various reasons.