I think that for a beginner who is just getting started with an SLR, this is a great all-purpose lens. It was my 2nd lens that I bought. The first was the 50mm f/1.8 just because it was super cheap and I was still deciding which other lens to buy as my "general-purpose" lens.
My pictures aren't the sharpest, certainly not to the degree of many of the images I see at my local camera club. Since I am just learning, I understand much of that is my fault, but part is also the lens. I consistently get sharper images with my 100mm macro, and 17-40 L-class lens, but they are certainly more pricy and thus ought to be better! Not to mention one is a prime.
IS is a cool concept, but I dont take as much stock in it as the marketing department. I dont know if my lens has the 2 or 3-stop IS (they claim they have 4 stop IS coming out soon!) I'll skate by with one stop slower than 1/focal but hesitate on going further. I haven't done any serious testing to prove to myself how well the IS works on this lens though, so I can't say much more.
I'd say if you can get this lens (mine was lightly used) it will be a good investment. I dont regret purchasing it, especially after taking classes. My pictures with this and my other lenses are noticably better once I learned how to use them more effectively.
When you get to be a better photographer (or hit the lottery or you are just rich) then go spring for a 24-70mm f/2.8L lens. I'm hoping Santa brings me one!