Personally, I have used both the Gmail alias and the [email protected] strategies. I have since given up both as I found it too hard to remember what address I used where.

The main reason I quit doing this is because Gmail's spam filtering kept spam out of my inbox and I never cared if one of those aliases were "compromised" and it wasn't worth the effort. I guess it was a solution to a problem I never had.

I still use a [email protected] for those sites that I may need to provide an email address and I don't want to give them my real address, such as forums that make you sign in to see an answer.