Yes, I know where to find illegal ebooks. <cough>usenet<cough>. Excuse me.
I find that if I enjoy an author, I either buy the book or borrow it from the library (my county library here offers a limitted number of ebooks in MobiPocket format, which is actually what got me using their reader).
The only books that I buy in pBook and then download are the Harry Potter books.
I tend to buy books in MS format so that I can down-convert to HTML and then reformat to my preferences. I haven't bought any Mobi content yet, and I can't say that I plan to. Actually, I can't say that I plan on buying ANY DRMed eBooks that I can't downconvert to some markup language and clean up...
Which reminds me... Sorry to change subjects on you, but has anyone heard that Amazon is no longer going to sell eBooks in PDF or LIT, and exclusively sell Mobi format? A friend mentioned this to me today, and I noticed yesterday that their "eBooks" section was removed, and tells users to go to MobiPocket.com -- but you can still find some books in the aforementioned formats. I know Amazon bought MobiPocket so this wouldn't be too surprising, but it does seem a bit extreme to me.