Hex editor that allows me to search bits and replace them

I've 开发者_StackOverflowfound AXE, it does it very well, but it's not free and I can't access the website (I would have bought it). I can't find any hex editor that is good and free, and has that feature, really.

You can use gVim to view a hex dump, replace bits and save. Since it's vim, you also get all the advanced editing tools.

Which platform?

I use 0xED on Mac OS X. It has a decent GUI, good featureset and is free. http://www.suavetech.com/0xed/0xed.html