Well, since I run my own mail server, I tend to use _ instead of + as the separator, simply because more places will consider it a valid address.
But it's amazing how useful it is to include the name of whoever you're giving the email address to in the email address. It lets you keep getting email for stuff like password recovery. And when an address is leaked, not only can you block that one, but you also get to know who leaked it.
Which is awesome for knowing which businesses to never use again.