New font for VS 2005
I've just come across Consolas Font Pack for Visual Studio. Once installed the consolas font will replace the default Courier New front in Visual Studio. This font is suppose to be easier to read on screen than Courier.
The font is part of the new font packs that are going to be shipped with Vista, I think the only one that has been official released is the Consolas font in the Font pack for Visual Studio.

On the face of it the Consolas fonts looks much clearer than the Courier font.
Note: Though you can just install the Font Pack without VS2005, I think that the licence for use of the font (outside of a Vista environment) is covered if you have a licence for VS2005 and have it installed.
I tried this at work in my VS2003 IDE and at home on VS2005.
This is a screen shot of the code using the original Courier Font (click on the images for original image)

Once I had installed the Font Pack I changed the default VS font to Consolas.

Hopefully you can see it from the screenshots that i've found the M and the L a bit difficult to read.
I've got installed the ClearType Tuner power tool from Microsoft, which allows be to tune my ClearType setting.
I don't use ClearType on my desktops because I find that the text is more difficult to read especially on windows menus. However I've switched it on to see what affects it has on the new font.

As you see that it was a little bit clearer, though the effects that ClearType has on the other parts of desktop, makes it for me unusable.
I'll give the new font a go at home anyway. The monitor that I use at home is alot better than the one I've got at work. I've found that the font becomes much easier to read above the default 10pt that the code is defaulted to.