Depends what age group you're in. David's and Wiley's (downtown) are both having New Year's parties. There's always dancing at David's and Wiley's will probably set up a dance floor for the night. There's a cover charge at David's but none at Wiley's. They are in easy walking distance. (about 4 blocks) If you want a little quieter night I'd suggest checking out Paramount (Piano bar) and Touch of Europe (live jazz/good food/drinks). Both of these are downtown also, about a block away from each other. You could ask the hotel concierge or front desk for directions. I'd suggest staying downtown so you don't have to get a cab. It wont be easy to get one on New Years.
The city also hosts a First Night party every year, but I don't know a whole lot about it. Tickets are $5-$20 and it gets you in to several places. They have an alcohol free ticket or a 21+ ticket.
http://www.firstnightsiouxfalls.org/