This list is gleaned from my server logs. If your RSS reader supports ETags or HEAD requests let me know and I'll add it here:
- NetNewsWire - latest beta
- Aggie 1.0 Release Candidate 3
- Radio Userland - testing code, see Dave's post
- blagg with DJ Adams' modified wget.
- Wildgrape NewsDesk [added 3 Feb 2003]
- nntp//rss [added 3 Feb 2003]
There seem to be a lot of home-grown aggregators too using Curl on Darwin, WinHttp, Perl libwww, etc.
[updated this list 3 Feb 2003]