Some 2000's had bugs, it seems the false O2 CEL is one of the worst ones. I'd go with the 02 if there isn't much of a price difference. As far as the "recalls" redgiki said, they are actually Tech Service Bullitens, not recalls. The only recalls on the 00 and 01's as well, both have a ECU recall, which will bring the software to that of the newer cars in the process appraently fixing some bugs. The only recall limited to the 2000 model year cars was a DC/DC converter recall which was limited to a small range of serial numbers.
The other mentioned things, window regulator and EGR valve are TSB's that apply to all years of Insight unfortunately.
And almost correct, most 2000 insights did not have factory air, but some of them did have factory air. You can tell by the VIN, it starts JHMZE13 then 5 or 7, 5 is no ac 7 is factory ac. If the dealer installed air is done correctly you should have no problems with it. I have dealer installed air, it works just fine.
And the other unfortunate thing I've come across with some 2000 owners is some have had pretty bad battery problems. Check the Yahoo groups, Drew in particular seems to have had the worst luck to the point where the car would recalibrate several times while he was driving. After having a lawyer pulled in to the mix they finally replaced pretty much his whole magic box and got it working like new again. But, this trend seems to be moving to some 01's and even 02's now, mainly in hot weather. Having driven a 00, 01 and my 02 I think there were some decent software changes from 01 to 02. But the ECU recall does get you almost to how a 02 or later is. I've been told there is a 04 flash too, so they may be even more different.