I'm pro-dollar amounts. It ties in nicely with the theme of the site. Plus the problem I see with the "Buy It/ Rent It/ Avoid It" Is that anything rated "But It" implies full price. There are some games that I want to buy, don't particularly want to rent, but don't want to pay $60 for and will wait until they are $40 or $30 it's a very all or nothing system.
I know Cheapy's concern is that proces decrease over time, that works perfectly. If you see that say Rainbow 6 Vegas is rated and average of $55 and now it's a platinum hits title for $30 or on clearance for $15 then heck yeah I should buy it.
Or there could be a combo, where the "official" reviewers use the "Buy It/Rent It/Avoid It" scale, and then the site's users assign the dollar value to pay. That would please everyone and allow for the majority to assign the value.
Why this would work: If you have just the one official reviewer assigning a score it could be skewed away from the average, so they should only be allowed to put it in general categories. The larger the quantity of rankers assigning dollar values the more it will even out (the larger the quantity of participants the closer it gets to a normal curve). For example,
Let's say Assassin's Creed comes out.
The "official" reviewer says the game is good, and fun, and he really likes it and he tags it with "Buy It"
Then everyone comes in and plonks in dollar values. The uber fans of the game can all say $60 but I thought the game was meh and worth $30 it will help to regulate the skewed average.
Yaay for numbers!