Typically speaking, if a game shows up as a daily deal, that'll be the best sale price all sale long. However, I have twice in the past seen a game at 50% during a daily deal and then 66% as part of a flash sale in the past. But it's not all that common to see the flashes be cheaper than the dailies. Also, keep an eye on the flash and community choice sales. Sometimes some real gems can show up in those. That's how I track down good buys during the wallet shrinking Steam sales.
Based on what's on sale currently, I'd put my votes in for Bioshock Infinite, Hotline Miami, Scribblenauts and Don't Starve. All were quite fun for me. If nothing else, I recommend Hotline MIami. At $2.49 it's a heck of a deal.
And to keep this post headphone-esque, I quite enjoyed the sound track for Bioshock: Infinite. That said, last I saw it didn't support Dolby Digital Live or DTS. This may have changed since I last played it. Skyrim does support Dolby Digital.