HP, Epson, Canon and Lexmark printers usually work with Macs. Check the manufacturer's website for system requirements. If you have any doubts, contact the manufacturer directly and ask about Mac compatibility. What kind of printer do you want and in what price range?
I don't know about webcams but I did a quick check on Logitech's site and was surprised to see that none of the listed webcams are supported in Macs. I guess now that most Macs (except Mini and Mac Pro) come with built-in webcams, other companies have stopped making compatible webcams. You might try a Google search for webcams and Mac and see if you find some that are compatible.
Some external DVD burners that are listed as PC only are Mac-compatible. I own an LG 5163D and it works flawlessly with a Mac. Before purchasing it, I contacted LG and received a quick, polite response, letting me know that it would work with my Mac. So, once again, my advice is to contact the manufacturer if you see a DVD you want to purchase. Some companies, like LaCie and EZQuest, have excellent support for Macs and include Mac-compatible software with the DVD drive, but others, like LG, only supply PC-compatible software. However, there are excellent, free DVD burning programs for Macs (I like Burn, but LiquidCD is another option).
Hope that information helps.
Claire
