Here's another vote for the Nexus 5. IMHO, the best Android phone on the market, and it's also the easiest to root, unlock the bootloader, install custom ROMs, etc.... and if you mess it up at any point you can always download the current factory software image right off the Google site. With a few clicks you are back to stock.

There are a million other reasons to get a N5. It ships unlocked for a reasonable price, which is nice for frequent world travelers like Flyertalkers. It's the first phone to get new Android versions from Google. My old Samsung Galaxy S3 (factory unlocked, international edition) is still on 4.1.2 because Samsung doesn't bother issuing new versions, they would rather sell me a new phone instead.

At least you should consider it on your list with the others. Read the reviews, give it a fair shot, etc.