We were hit in an early panda iteration and had a lot of trouble coming back. It wasn't until last week that we recovered, and the traffic graph from Google organic search looks like a capital L flipped on its back followed by a hill that continues to rise.
We tried EVERYTHING. Go through any list of stuff to try to come back from Panda and we probably did it. But when it comes to "removing low quality content" we at first chose to use follow, noindex tags because our "low quality" content was still useful to some users if they were searching for it on our site. It turns out, at least with our experience, that Google actually wants you to remove the content from the site, not just noindex it. Once we deleted the content (thousands of pages) and either let it 404 or, in some cases in which they had external links, 301 it to the closest category page, we made a comeback in the very next update.
We redesigned the site, went through days and days of filing DMCA removal requests for old, syndicated content (9 times out of 10 they'll remove it instead of digging out the contract or email that says they can use it); deleting content when the syndicating site refused to remove their version; cutting down on Adsense units and moving the remaining units below the best content; removing any content that was too similar to another piece of content (e.g. ten ways to skin a cat Vs more than one way to skin a cat); searching with a fine-toothed comb for any duplicate content problems and fixing those; continuing to build very high-quality links the entire time; increasing time spent on site, pages viewed per visit and conversion rates while reducing bounce rates... You name it, we probably did it.
We were at the end of our rope. Our last effort was going to be a TOTAL site relaunch with new content, new taxonomy, new design - but on the same domain and with the same brand since we've built an impressive, defensible, high-quality link profile over the last couple of years, not to mention our branding efforts. But if that didn't work we were going to scrap the site.
Two weeks before the launch of our new site we came back. Go figure. But the only big difference between now and the last Panda update was that we deleted the content instead of noindexing it.