I'm sitting on 3 DSLRs right now, a 6D, 60D, and XSi. That's 1 too many (I want to keep one of my crop bodies around as a backup).
Trying to debate which crop body to keep.
The XSi is obviously older (purchased 2009 vs 2012 for the 60D) and will fetch less money. I like the super compactness and the idea of keeping around a really cheap used DSLR as a beater is attractive.
The 60D is a lot newer, and I definitely enjoy shooting with it more than the XSi for the IQ, better high ISO, and definitely ergonomics. But my new 6D covers that and more. So maybe sell the 60D and get a bit more money?
The camera I choose to sell, I'm going to sell it as I purchased it. So the XSi would be with the 18-55 IS kit, the 60D just the body only.