How do you actually manage reading those diverse email streams (until they get spammy)? Do you forward them all to one address and read that, or are you actually managing separate mailboxes?

The former. In practice, nowadays I forward that domain to my Gmail box, which filters out at least most of the spam, and I use filters to slice off addresses that are clearly doomed.

(Note that this is effectively identical to using Gmail "+" addresses, but doesn't give away my Gmail address, and is less likely to choke craptastic emailers that don't properly understand how email addresses work.)

That said, I should also note that my *professional* domains (eg, querki.net) get fed into Google Apps and managed that way. That's more effort, but helps maintain proper firewalls between the personal and professional.

Oh, and I should note the downside of this approach: some less-ethical crooks will take your domain and simply invent addresses in it, and then sell those on to the people buying email lists. So it is quite common for me to get *scads* of copies of some emails, to different ridiculous addresses on my domain. Those are the addresses most likely to simply get filtered...