Up until last night this was not an issue and other than the phone (3Gs on iOS 5.1.1) backing up to iCloud nothing else had been done, changed, or otherwise modified.

I can open Safari. I can select the address bar. However, within a second of typing anything Safari crashes out to the home screen. This will also happen if I open the bookmarks menu. I never actually get to *see* any bookmarks as just pressing the icon causes a crash.

I am, for whatever reason, able to type in a search and go to websites from there without issue. As soon as I attempt to add a bookmark (normally or to the reading list) then I'm back in Crash City.

Some things I have tried:
- uncoupled the bookmarks from iCloud and synced directly from my computer instead. (still crashes)
- removed bookmarks from the phone entirely. (still crashes)
- tried copying a known good url from Notes and pasting it into the address bar. (still crashes)
- restarting the phone. (still crashes)
- clearing history, cache, disabling javascript, and changing to private browsing -- all together and separately (still crashes).

I haven't tried wiping the phone and reinstalling iOS yet, but I was hoping that wouldn't be necessary.

For posterity, a nuke and restore fixed it.
Still don't know what caused it, though.

Good to hear that you got things fixed and working, even though a bit drastic, but a "N&P" usually works.

I think my eldest son was one of the first to coin the "Nuke and Pave" phrase some years ago when training some Yukon school support staff back in the old Mac System OS 8 and 9 days.

And it still works, even if a bit of a drastic method, but sometimes it's still the only proper solution that works using the old "Nuke and Pave", and the phrase still seems to work it seems. ;)