Agree with most comments. I know I bought my 04 last August with 5600 miles on the clock for $13 even. It's worth more today than then but part of that is the revival of the used car market. Cars go down in value for lots of reasons but also maintain or go up in value for similar reasons -- age, rarity, condition, color, history (maintenance, reliability, etc. etc.), demand, and lot's of other factors.
From what I've seen, XFires are doing better than others. Heck, I'm looking at a second XFire this weekend (high mileage and needs alittle cosmetic work) and it's priced higher than a lower mileage really nice BMW 2 door with the sports package -- which is actually tempting me to buy it instead of the second XFire. The BMW has way more features, four seats, is in much better shape and is an automatic (which I only prefer because this one would become my daily driver). With that said, I'm still gravitating to the XFire for several reasons. I love the car.......it's so much fun to drive, is more unique, could be used as a parts car for my existing car if necessary, and I would like to keep an XFire as a daily driver.
If I can get the dealer down to where I want, I'll likely buy it (if it's mechanicals check out). We'll see.