Hi Lun,
You're prolly getting stomped with these but I thought that I would hold the Linux banner a little higher considering most (not all) fo the other posts are speaking of Windows stuff.
I like a program called Cool Edit. Tons of features and fantastice syntax highlighting that really stands out. Some of the other things that come with it are kind of dumb, but otherwise, it's a winner.
You could also check out Code Commander and Nedit. Both seem to do some really cool things are well developed (no or few bugs).
If you want a Homesite clone, check out Quanta. It's a KDE prog, but it will run in Gnome or whatever. I've used it under WindowMaker and Enlightenmnet. Tons of features like Homesite, but the text is difficult to read with little options for configuring. The highlighting is a bummer too.
Oh well, hope this helps on the Linux front.
See ya,
Terrence