I like Yahtzee's rating system

This game sucks

or

This game sucks but still play it

I would make a picture system, ranging from a cock and up to jesus.

Omnidum:
I would make a picture system, ranging from a cock and up to jesus.

but wouldn't that be more subjective depending on a few factors including certain preferences? and what would happen if you're a female christian or a gay christian? would the rating be good no matter what?

I like a movie-style 4 star system with the following distinctions, usually these are what SHOULD classify a drop, or raise in numbers. Now very little would fit ALL of these categories in any one rating, but I think these are good classifiers overall, and they should encourage people to read the review to see where the game hits within this criteria, I found MANY reviews make a lot more sense if you actually read the text as opposed to simply looking at the score.

4 - Universal Appeal, Plenty of Artistic and Mainstream merit, High Fun Factor, Long Playtime or Lots of Replayability.
3 - Wide Appeal, Either Artistic or Mainstream Merit, Good Fun Factor, Worth Playing at least Once.
2 - Narrow Appeal, Merits are very selective, its fun but can be either taxing/frustrating, short/no replay value/too long.
1 - For Fans Only, Merits based on dropping your standards, fun is limited, short with no replay value.
0 - Postal Series.

or to make it easier...

4 - Buy It unless you KNOW you will hate it.
3 - Think about it, read the review, then buy it.
2 - Rent it first, you may have misgivings.
1 - Think about it, read the review, rent it, then, if you still love it, buy it.
0 - Games like this are bad for you, me and the games industry.

A few people have touched on this, but I don't like numerical systems for the fact that they have too much subjectivity. What's the real difference between a 9.0 and a 9.3 anyway other than statistics? It's just not a good way to really rate games.

Further up on the scale is any kind of letter system - at least with the kind of scale you are used to with school there is a clear siloing of ratings - A is obviously excellent, B is good, and so forth with a plus or minus serving to fix the whole "tweener" problem for some games. But it's still a bit too subjective.

In my opinion, the simpler the scale, the better. That's why try it, buy it, screw it is probably best. It forces reviewers to think about what they are playing and put it in a bucket that best fits it. It leaves little if any confusion on the part of the reader as to what the ultimate outcome of the review is. And it's dependent solely on the reviewer's opinion rather than some vague agreed-upon idea about what constitutes one grade vs. another. I find that these are the best reviews to read - although honestly, the only one who can make a decision about a game's worth is the reader.

I used to follow what PC Zone used to say which was a % score. However I don't follow scores anymore I buy games I think look good and make my own judgement which is either i like it or not.