I was using Firefox on PC and Firefox Mac was able to use the profile folder I transferred over. But there’s a program called Move2Mac that will do pretty much everything for you in terms of migration.
As far as printers, Dell uses standard printers like Lexmark, just with a Dell logo on them. Most likely your printer will work right off the bat.
Just started a switch myself. Homeschool my 2 girls, and we are determined to keep them computer saavy. Have had a mac mini for about 2 months now. by the end of week 1 with the thing, the kids (14 & 11) had thrown together a DVD presentation on a summer-youth-camp-thingy and showed it at youth group. They are liking it, and I think the next mac purchase will be about Christmas...
I will probably have at least a couple windows boxes going for a few years, but I hope my dual-core Dell is the last one I have...