I watch a lot of fansubbed anime & find I prefer Zoomplayer http://inmatrix.com/
I also am using a 6 year old IBM laptop that isn't too powerful & I find Zoom uses less memory & less processing power. Therefore less lag & better rendering.
I believe this is due to the fact that the actual Zoom player is a sort of framework and all the codecs are external.
It used to be a beast to set-up the codecs but now it has an excellent codec installer which downloads the latest needed codecs (you have control over which) and installs them, usually perfectly.
The only thing I found recently was that I couldn't get it to play Flash .flv although I had Flash installed. Turned out I had Flash installed on Firefox & Zoomplayer needed the IE OCX control - once I fired up IE and installed Flash it worked fine.
Zoom is well-tuned for speed & accuracy and handles subtitles beautifully with complete positioning & display options including font selection.
There is even an U3 version that runs from a USB stick http://software.u3.com/Product_Details.aspx?ProductId=114
It is of course a paid Windows application so I guess everyone here is going to put it down.