[JKT]

For a thorough listing, let's not forget to include what unique features OmniWeb offers as well:
- Workspaces
- In depth site-specific preferences and site-specific download destinations
- Simple RSS interface (nice for some, too simple for others; UI could be nicer looking either way)
- Thumbnail tabs which can be manipulated in full (drag and drop sorting; copy/cut/paste- able)
- iDisk/WebDAV synching (could be improved to include Workspaces, Cookies, etc)
- independent text input field editor
- Source editor
- Save as single page PDF
- A useful download manager
- Powerful bookmark/history searching
- URL completion that doesn't suck
- URL addition to comments field of downloads
- Bookmark sharing


A few others to include in the mix:

Opera
- Zoom display

Firefox and Opera
- Scaled images (to fit the browser window if they exceed the boundaries)

For me, the features from the other browsers I'd like to see are:
1. Better RSS feed UI
2. Scaled images
3. Better archiving of pages (e.g. pdf's with active links).

Extensions/extensibility might be nice (though they aren't without their own issues in Firefox), but I can't really see anyone developing any for a niche browser on a niche platform.
Themes just don't interest me, but I understand that others would like them.