The missus wants a serious camera after borring my D100 to shoot a stock car race at Lime Rock Park last weekend. We're not made of money enough to get what I'd really like (D2x), but I figure a D50 would be adequate for sports photography as well as the occasional artsy-fartsy shot. Then we see the D70 and D80. They're both OK budget-wise but I haven't quite figured out what makes one better than the other. Better put, is there something on the D80 that isn't on the D70 that you can't live without, and the same with both the 70 and 80 relative to the D50?