My first experience in a manual transmission car was driving my M3 off the lot. That said, while my car was on its way from Germany I read everything I could find about how to drive a manual transmission properly, best practices, things to avoid, etc. I also did research into how a manual transmission actually works, which was not only interesting but gave me an appreciation for WHY the best practices and pitfalls are what they are. I even created a thread here called "Advice for first-time 6MT owner?" that generated a lot of helpful information.
Honestly I wasn't very worried. Before picking up the car I felt like I'd learned about as much about driving stick as one possibly could without actually doing it. So I drove home very carefully and then went out late at night for several nights just going around and around some residential blocks to get a feel for driving stick. I definitely stalled several times in the first few weeks and had some really jerky shifts (my wife wouldn't ride in the car with me at first due to headaches from that), but I got the hang of it pretty quickly. The M3 I'm told is a pretty easy car to learn stick on, although I think the the regular 3 with its CDV is even easier; it's hard NOT to shift smoothly in that.
And now about 1.5 years later it feels totally natural (and awesome), and I've been heel-toeing on the track the last few times I've gone. I've driven DCT M3s a few times and I do admit that they're fun in a different way since there's a higher sense of speed and immediacy when shifts are so fast and you don't have to take your hand off the wheel. But I figure I'm 26 years old, so while I'll have plenty of time to enjoy great DCT cars in the future, 6MT may not be around for much longer, so I'll enjoy it while I can. Plus even though DCT MIGHT be make track and twisty back road driving slightly more fun than 6MT does, 6MT definitely isn't boring there, but it DOES make driving that WOULD otherwise be boring (commuting, casual street driving) a LOT more fun than it would be in DCT. Now of course if I spent lots of time in traffic, that equation would flip. Plus, especially since I'm a newer 6MT driver, I still love the thrill of always chasing those perfectly rev-matched shifts and feeling like a total hero when I get it just right.