Yeah I've been using activestates komodo (for linux though it comes in both windows and linux flavors) since around 1.x when work found it a worthy enough editor to buy for us.

It has tons of neat features but is kinda resource hungry if you are just after code highlighting.

Though not unique to komodo my favorite feature is the whitespace view because I hate when you see whitespace before code that would match /\s{2}\t\s\t{2}/;

It's not OSS but IMHO it's worth a look.