If you decide to go for a dryer that's on the higher-end, you can get a pretty good deal from Folica.com. Basically, you send in your old blow dryer and you get a $40 off coupon to apply to any blow dryer priced over $79.99. Details here: Folica.com - The best selection of hair care, flat irons and hair styling products anywhere
I traded in an old Revlon blow dryer I had gotten from CVS a million years ago and they accepted it. I was nervous about what they would accept, and so I gave them a call and they said any brand is fine.
I ended up getting this one: Solia 1875W Thermal Ionic Hair Dryer | Folica.com
Overall, I really like it. I'm not sure how much the ions etc. help, but I feel like it dries my hair really well. I noticed a lot of shine when I used to blow my hair out straight every day for work, but I really can't say whether I'm imagining it or not. It has a super long cord, which is nice, because I have an awkward outlet setup. It is pretty heavy though. I did like the fact that I could "upgrade" to a fancier drier for only $49.
So yeah, I'm not really sure how much it helps, but if you decide to go for it, you can get a pretty good deal there!
ETA: it does *not* come with a diffuser.