Hi advaita,
I realise that you were joking with the 20% quote, but on a serious note.
I dont mean to come across as preaching, but I think one of the main mistakes that newer entrants to the domain business make is mistaking the line between development and domain names.
Google.com would be worth $0 as a domain alone. With development, worth $80Bn? (give or take) now. Weather.com as a domain alone would be worth about $5M or so(guess without knowing traffic before development), with development $5Bn. DasWetter.tv is worth 10-20x yearly profit (of course taking away reg. fee costs with tv). With development who knows, but now, unfortunately $0.
Of course all these are market prices for domains. There is of course the odd domain that sells to an enduser for a price irrespective of branding and/or earnings.
Sorry for the long, and possibly flawed post, but just something I've noticed being in the domain business I'd like to point out to save newer people money.
Big difference between potential of a domain and inherent value.