I just learned about the King George Hotel about a block away from Union Square. I haven't stayed there before, but I'm a TA and a rep came by a couple of weeks ago to promote it. They have some good deals for packages starting at $129 including parking and breakfast. Don't think it will provide you with a great view though.

I've also stayed at The Palace and the Grand Hyatt. The Palace hotel itself was great, but our room was nothing to write home about and I was given upgrade. I really enjoyed the view and location of the Grand Hyatt.

website for the King George is www.kinggeorge.com