One note of caution with getting a PRS-500.
The difference in Contrast really stands out between the two generations of screens, and I personally can't really stand to read on the 500 after getting my Gen3 which has Vizplex screen.
If you don't think your husband will mind the difference, then go on and get it. Otherwise it may be worth considering buying a 505 if you can get a good deal somewhere. You could always ebay it if you don't want to keep it,
Other then that the 500 is a nice machine (especially if you have it hacked

)