An Intel mini was also my first entry into the world of Macs almost 2yr ago. At the time my former windows box was over 3yrs old. I was wanting to upgrade some things about it, it REALLY needed a reformat and reinstall, but I was also interested in trying out OSX. Id actually kicked around the idea of getting a mini a few years before this (the first g4 minis) but when it came time to buy I couldnt get myself to do it.
I looked at it like this: I could still use my keyboard, mouse, and monitor with the mini. I could get into the world of OSX, which I knew NOTHING about, relatively cheaply, for $799. That seemed better than plunking down $1200 for an iMac. BTW, yes there was/is the $599 model, but I needed the superdrive.
With the Intel machines it became less of a risk. I could always run XP if I wanted to. Thats really what I had intended on doing when I got my mini. I was going to run XP in bootcamp as my primary OS, then explore OSX and get to know it on the side. But I never installed bootcamp, and OSX became my primary OS from day 1, and Ive never looked back.
After getting my mini I got my wife a macbook a few weeks later. Then a few months later I got my younger kids an old iMac G3 DV for an internet machine.
And just a few days ago I ordered myself a 20" iMac to replace the mini and got my wife her 2nd macbook. So basically the mini because the entry point to Macs/OSX for an entire household.
The mini may not be attractive to alot of PC ppl because you see this small little box and think "for $799 I could buy myself ALOT of pc hardware and make a very up-to-date PC." That was my exact thinking. I debated back and forth on the mini. I actually had to just buy the mini on the spur of the moment without giving myself much time to think about it because Id likely have talked myself out of it again.
Like alot of Windows uers, the OP is only looking at the price tag. "Just spend $300 for a cheap Vista box." Well on the surface yes, you can get budget priced Windows pcs that are alot cheaper. But the whole point is none of these pc will run OSX. Lets face it, the Mac experience is about OSX. The hardware is nice, while still more pricey than PC hardware, you are essentially paying for a machine to run OSX. You really need to get past the price tag because you arent just buying a piece of hardware. You cant compare $300 budget beige box with a mini. You are buying a more pleasurable computing experience. It was hard step to take for me because OSX/Mac was like a foreign land and language that I knew nothing about. But as many, many people say, I wish Id done it sooner.
I will say that even after almost 2yrs of using it, Im still AMAZED what the mini can do for such a small unit. And one of the best aspects of it is its whisper quiet. My last windows box had 4-5 fans in it and sounded like an airplane taking off. The noise from those fans was soooo annoying.