Ahh- the question is, short term or long term costs? That can be hard to determine.
I've been shocked at how many of our PCs I will need to replace (almost all of them). They won't be upgradeable to W7 from XP Pro or Vista, hardware wise. MS called last week, to remind me of EOL on XP. But I just don't see us replacing everything this summer. Especially since our server is 8 years old and is way past replacement time. My, how time flies when you're not having fun.
Anyway, I looked at doing the XP mode thing under W7 64, but decided to be on the safe side and stick with 32 bit, since our accounting program will not work with 64 bit. XP mode would probably have worked well, just not worth the hassle, considering we are having problems with that program, and they will not support it if it is running under 64 bit, even using XP mode.