I never owned a lot of domains (15-20).
But they are either in use or if the project went haywire I let them expire.
Though, two of them I'm still keeping since I like them, and maybe they'll be useful one day.

I had to post I keep it, but the truth is I sell them on.

I have this week sold 2 domains for £500 a piece.

I own quite a few nice .eu domains. in finance, debt consolidation etc.

I also own a couple of nice ones for email addresses that we are going to be selling.
I own things like (and here is abusiness opportunity for someone). athomeinwales.co.uk
athomeinthe.eu
athomeidevon.co.uk

the email addresses are then
oldwelshguyathomeinwales.co.uk
oldwelshguy@homeinwales.co.uk
How easy is that to remeber ? and at £10 a year to rent damn good value.

I also own inwales.or
inwales.eu

so the subdomains are

builders.inwales.eu
restaurants.inwales.eu
webdesign.inwales.eu

again £15 a year secures you a great subdomain

I am not selling this to you by the way, I am pushing a concept. As domain names get harder to get hold of, sub-domains will fill the gap IMO.

You are quite righ about the sub domains, that is what centranic live off, domain like eu.com, uk.com and other sub domain they are flugging for £50 for two years

I do own a few domains, I have reluctantly let a few expire but I keep most of them even those that I am sure I will not be pursuign the project any more but I just kept them for fun and interestingly, I do get a few bob from such domain now and again when people contact me out of the blue asking to place adverts on the site, on of the domain is about 10 years old, its listed in DMOZ but I am just not into what the name is about anymore (computer games).

Thats a really good idea welshguy. All the good domains have been taken now so they will become extremely ppopular.