I'll give you all a little selling "secret". List your item with a low opening bid price ($1 or less). This minimizes eBay's listing fee because it is based on your opening price and it also encourages people to look at your listing (I don't like looking at listings with 0 bids and a $49.99 opening price). Use BuyItNow! and set it to a fairly high price, a price where you have some doubt that it is feasible for a sale, but might be. Finally, set a reserve for some figure between the opening and BuyItNow! price.
For instance, let's say you have a used 24x Lite-on CD-RW to sell. You list it for $0.99, set the BuyItNow! price to $79 and the reserve price to $60. If the first bidder places a bid for $0.99, they won't make the reserve, so your item is "safe". However, because you used a reserve price, the BuyItNow! function is still valid. You are right, it sucks how BuyItNow! is disabled after the first bidder places a bid. However, using reserve price keeps the BuyItNow! function available UNTIL that reserve is met. So if the second bidder bids $25, the reserve still isn't met and BuyItNow! remains available.
See, if you are a bidder and see an item for $0.99 with a BuyItNow! price of $79, you don't want to use BuyItNow! because you think "heh, I'll get it cheaper than that $79...it's only 99 cents now!". But let's look at my reserve price example. Say the auction has a few bids and the price is now $50, not $0.99. BuyItNow! is still available on the listing. Hmm, maybe a bidder will end the auction and pay the $79, seeing the smaller price gap. I've used this method many times and it works more often than not. I get a desirable BuyItNow! price AND a shorter auction duration.
The only risk to using this method is that if the reserve price is not met, you have to pay the reserve listing fee. Otherwise, if the item sells, the fee is waived.