I write up the body of my auctions in FrontPage2000. You just have to be careful when copying the HTML that you don't get something that Ebay will not use. I think my auctions look pretty nice and I keep templates in my FP2000 for the various magazines that I sell so I don't have to retype basic information over and over. So far I've not run into any problems because I don't get really fancy in case someone is using an older browser.
There's another neat HTML editor out there called Coffee Cup that is pretty neat as well.