Stand Mixer 101 !
You need to search the boards. While you are doing that, there are several things to look for:
1. What do you want to mix? The Artisian is great for most tasks. However, if you are making several loaves of bread a day you may want to look for a more powerful mixer.
2. Tilt Head vs. Lift Bowl - The difference is how the mixer possitions itself to allow beater changes and bowl removal. Tilt heads such as the Artisan tilt their heads up to allow for these functions. Lift bowls such as the Pro 600 lift the bowl up and down. Usually, lift bowls have a bigger capacity and allow the use of the water jacket accessory for temparture control during mixing (vs. freezing or heating the bowl).
You know, I think you would do well to consider the Cuisinart mixers. More power, better warranty, somewhat better construction, many of the same accessories that have made Kitchen Aid the standard for a long time, and priced in the same ballpark.
Full disclosure: I don't have a stand mixer, but did have an old KA hand-me-down (60's vintage oddball) that eventually croaked. The old Kitchen Aids were pretty awesome, but the newer models, well, you read of some reliability issues. My guess is that most of these issues are with people over-loading their machines, but also pretty sure that the newer models are not quite as robust as the older models.
I've had two Kitchen Aids. My current is an Artisan, and it works for me, though I think I did prefer the larger size I had before. I switched out for color only, so consider that decision carefully!
One word of caution. In my experience Kitchen Aids are pretty reliable, except for one thing. The serial number information is on the bottom. You CANNOT turn it over to read it however. OK, you can, but you will break an internal seal if you do so and you will have to have the mixer repaired. If you're out of warranty, this will be on your dime. So ... don't do that.
I am generally all for marching to a different drummer, but when it comes to important kitchen equipment, I have never regretted investing in the gold standard.