I'm in a similar position to the original poster. I use a PC at work and I currently use MacOS X at home, although prior to that I used Linux.
With Linux I had some success with running Textpad under Wine but for the Mac I have been attempting to get by with Smultron for most of my editing needs. Smultron's a
good editor but is not quite Textpad in my eyes.
As it happens it is not usually a major issue for me since most of the time that I need to do serious text editing I am at work. Also my work machine is a notebook and I often bring back home with me anyway. Although on occasion I have
seriously missed having easy access to Textpad.
The other day I bought Wildedit and I'm already addicted. In the past I had used sed but I prefer working with Wildedit as
one off stuff is so much quicker/easier. (Although I think sed still has the upper hand if you need to make the exact same edits again and again, due to the fact that you can write a script/batch file for it, whilst Wildedit seems to lack Macros [someone correct me if I am wrong]).
Anyway, this weekend I dug up an old copy of Windows 98 that I once had for a laptop that has long since died and installed this under
Q[kju:], a MacOS X port of
QEMU (an open source processor emulator), with a nice front end. You can gain access to directories on the MacOS X host via CIFS/SMB file sharing that Q helpfully sets up for you.
Win98 runs at a workable speed under the latest unstable build of Q (0.8.1d35) for me at least. (I have a fairly recent flat screen G5 iMac).
Now if I have to do some serious text editing and don't have my work notebook to hand I can fire up Q+Win98 and use Textpad and/or Wildedit. You can even save the Win98 session in a state with Win98 already booted and both Textpad and Wildedit already running. (Of course for anything that isn't too advanced I will simply use Smultron).
This assumes of course that you have an old copy of Windows 98 and don't consider this whole setup an overkill (many would).

If you have an Intel Mac you probably have a few better options, with potentially more if Apple add virtualization to future versions of MacOS X.
As time goes on I'll probably transition to one of the great MacOS X editors full time when I'm using the Mac. ... Then again, maybe I won't! TextPad/Wildedit really are that great!
