Cool, thanks for the responses guys.
I didn't phrase my question too clearly, but Coppermine Celeron 1.1Ghz was the answer I was looking for.
So there's the FC-PGA celeron, then FC-PGA2 celeron, and now Tualatin-core celeron. Each step up requires a new slotket design. Except for the (overpriced) Powerleaps, the only slotkets available are for the FC-PGA. Celeron 1.1Ghz comes in both FC-PGA and FC-PGA2 flavors. I have to make sure to get the FC-PGA one for it to work with the Tekram "flipchip compatible" slotket I got right when the flipchips came out.
Am I wrong on anything?
And can I still use the GlobalWin 25603-16 heatsink/fan that I currently have on my Celeron 366->578, or do I need a bigger HS/fan?
The Duron/ECS combo seems to be the best value at the moment. Fry's has Duron/ECS combos in the $89-109 range almost every week. (Do any reputable online vendors have a similar package?)
It's mainly the ease of upgrading with another Celeron, and the ability to continue to use all 4 of my 128MB SDRAM modules that is keeping me from going in the Duron direction.