If its a domain you really, really want and are prepared to spend at least $500 or more then secure as many backorders as possible from every where. Do not and I repeat do not rely on Godaddy BO service alone. You will lose that name 90% of the time. All the fucking BO does is place a $10 bid if the domain goes to auction. Fuck godaddy and all their bullshit.
All other BO's will go to auction only when there is BO's placed by more than one person. Most of these places like snapnames, namejet, and pool will make the auction private which is nice but it is a blind auction.
So, when it comes to domains that you have an interest in do not rely on bull shit appraisals or what the fucks at DP, WaFo think its worth. What it's worth is solely up to you. Set a ceiling amount that you be willing to go and be prepared to go over it if you feel you can win with just another bid or two.
Once the domain is captured learn the auction house rules. Learn when to bid as most increase the time if a bid is placed late like crapdaddy.
The bottom line is if you plan to keep this domain for years to come then paying a large upfront fee to acquire it is not a big deal.