Personally, I like to stay in the DT area of Sacramento when I'm in town. I usually stay near the Convention Center (due to business needs) which provides a location that has a lot of nice restaurants within walking distance. To the west of that location is 'Old Town' which is fun and interesting if you've never been there (music, restaurants) and, to the east, around 28th & K Street is a club area if you want restaurants/clubs/music/dancing. About two blocks away is the state capital building and you can tour it if you like that (there should be some beautiful flower gardens on the grounds in late April). There is also the Railroad Museum within walking distance. The Sacramento RiverCats play AAA baseball just across the river in a very nice stadium that's just a short cab ride from the center of town. If you like baseball it's a very nice, new stadium and a good value. There is also a DT shopping mall about 7-8 blocks from the Convention Center if you want to spend some time there. If these are things you are looking for you can probably skip a rental car and just cab in from the airport. Most everything above is walkable or a short cab ride away.

My personal choice of hotels is the Sheraton Grand at 13th and J Street. Two blocks south at 13th and L is the Hyatt and two blocks east of the Hyatt is a new Residence Inn at 15th and L Street. (In DT Sac the east-west streets are in alphabetical order starting with A on the north and proceeding south; the north-south streets are numerical starting at the river and going in higher numbers as you head east. It's a pretty easy system to tell how many blocks you are from a point of interest.)

I'm not that interested in hot tubs so I can't really help you there but you can check the facilities listing on most hotel sites. Most all Residence Inns offer free breakfast so I would think that would be a match. At the Sheraton I've often been able to book a stay with breakfast included in the rate and the breakfast buffet has always had a lot of selections and/or they would let you order off the menu if you preferred. I've never stayed at the Hyatt but I've dined there (twice, for dinner) and the food has OK.