Hi HappyDomains.
I'm no expert on domain values (!!) but I just wanted to say scarcity is an important factor. This principle makes a mockery of any stratospheric appraisals. It's logical.
For example, your domain iFiremen has no scarcity. eFireman is readily available so even if your name had a high value (unfortunately I don't think it does) nobody would pay that value when a perfectly good substitute is readily available for £6. Therefore, at the moment, it can't be worth more than £6 - somebody may be foolish enough to pay more, but that's a different matter.
Conversely, the domain name LowPrices.co.uk has alot of value firstly because it's a great name, but secondly it has scarcity. Try to find an available substitute for the word 'low'. There just isn't anything of that quality available.
Oh well, just wanted to make that point.
All the best.
Steve.
Ps. Whoops, just realised I've bumped an old thread here. I bet iFiremen has sold to a Stripograms for 6 Gs. That'll teach me !