If you've installed some of your favourite Windows fonts in Linux, you may notice they don't show up quite the same. If your custom-installed fonts are looking too bold in Linux, you can fix them by tweaking your font config file.
After installing some Windows Vista fonts on my new Arch Linux installation (including my personal favourite, Candara), I found they didn't look anything like they did in Windows or OS X. Tweaking the anti-aliasing and subpixel rendering in my font settings didn't do very much to help, either. It turns out the problem is FreeType's auto-hinting. While some distributions (like Gentoo, from what I hear) disable auto-hinting for bold fonts, others don't, which for some reason causes many Windows fonts to look bold even if you haven't set them as such.
The fix is simple: just open up your ~/.fonts.conf in your favourite text editor and add the following block of code:
<match target="font"> <test name="weight" compare="more"> <const>medium</const> </test> <edit name="autohint" mode="assign"> <bool>false</bool> </edit> </match>
I found that after doing this, all my fonts looked like I remembered them, and I was open to using much more than what came with my distribution out of the box. Hit the link below to read Arch Linux's wiki page on configuring fonts—which should work with other distributions besides just Arch—and share your most useful font fixes in the comments.
Font Configuration - Disable Auto-Hinter for Bold Fonts [Arch Linux Wiki]