I'm a PC user as well, and recently acquired a Mac mini (1.42 GHz, 256 MB RAM, since self-upgraded to 1 GB RAM). My recommendation: Get the 1.42 GHz with 80 GB HD and either 512 MB RAM (from Apple) or, if you want to go to 1 GB RAM, get the 256 MB RAM option from Apple and then upgrade the RAM yourself... you'll save a couple hundred dollars by upgrading to 1 GB RAM on your own (you can resell the old 256 MB RAM module). Make sure you get at least 512 MB RAM, one way or the other... 256 MB isn't really enough for things to run smoothly with multiple applications open simultaneously.
Whether you opt for the SuperDrive depends on whether you want to burn DVDs using your Mac mini... so if you want to do this, or think you might, go ahead and do it. (I burn DVDs on my Sony PC, so I just went with the combo drive on the Mac mini.)