Fun, hip hotel with a Vegas vibe.
Loved my stay at the W Austin. I was upgraded to a Spectacular room with a King Bed, which is the W's third room tier, I believe.
The hotel is very trendy with modern decor, and has a fun Vegas vibe with music playing throughout. The lobby which is called the Living Room is a fun, comfortable place to hang out and access the internet. Staff regularly asks you if you need anything.
My room was amazing, I didn't want to leave. Lighting was cool, furnishings were modern, colorful and stylish, bed was fabulous, and had a nice 32 inch or so HDTV. The bathroom was awesome, with a beautiful, sexy (how else to describe it) shower. There is no door in the shower area, so you have to be comfortable with your roommate. Don't worry the toilet area has a door. 
The pool area is definitely a party, people watching area. It is only 3 feet at the deepest, so not much swimming. Its a social pool not a swimming pool. Bar and food is available at the pool. 
Easy access to some great restaurants and coffee shops. I thought it was easy walking distance to downtown, the Capitol (although a good walk), the bats, and sixth street bars. Gay nightlife is just a block and half away. Also, the whole area is very dog friendly, if you are traveling with your best friend.
I can't imagine a better choice when staying in downtown Austin.