I had my teeth professionally whitened, and I wish I hadn't. They have become very sensitive and feel almost rough to the touch. You can't see this roughness, but I can definitely feel it when I run my tongue over my teeth. I think this has something to do with the enamel.
They are very white, but sometimes I think they look transparent.
I use Blanx toothpaste, which is great. I currently have the "Intensive whitening" one. Obviously because I've had my teeth whitened, it's hard to tell if it really makes a difference, or not. However, I do drink a *lot* of black coffee, and my teeth are still white, which I think is due to the toothpaste.
I really wouldn't try any home bleaching kits. I have one in my fridge, that I've had in there for months, but I'm too nervous to use. It says on the leaflet to use for "2-3 hours" at a time, but the lady who did my teeth says she leaves hers in overnight and just "puts up with the pain". EEkk!