I would ask $450 for the first system, and $600 for the second one. Vista hurts it's resale value.
Wow that is a lot more than I had them up for sale on my local classifieds - I was asking $275 and $500 respectively, I really appreciate the input. Question, if you don't mind: I have a Windows XP Home license I could put on the 1st, would you recommend that? Or would it be better to buy a Windows 7 Family upgrade pack (3 upgrade rights) and upgrade both to Win7 Home Premium? The family pack is $130, do you think the recovery from vista would be worht the investment in 7?
I would leave the systems alone. Let the new owner decide what operating system they prefer. Skip the classifieds, unless it's free or low cost, such as greensheet. Craigslist is free, as is anandtech's for sale forum. There are so many computers for sale it may take awhile to get someone to stop by and check them out. And your original prices may be ok; I just ask a little extra for hagglers.