I have just bought a copy of DrWho's great new automated valuation programme, it goes through all the valuation requests in DNF and alternates between posting "$0" and "reg fee" as valuations. It saves so much time, I would recommend that we all buy a copy!
But seriously, no offence DW, any name that gets 300 uniques a day is worth money. Traffic = money, it is that simple. The name on its own is truly only worth the reg fee, if that, but it is not worth selling with that kind of traffic, Develop the site and put affiliate links on for financial services type products. You could easily make a couple of hundred a month in affiliate commission.
How much would you pay for an annuity that paid you ã2,400 a year? At least ã50k. With that extra income stream coming in it would not be worth parting with the domain.