It's a couple years old, but my trip report from there may be useful:

http://www.fodors.com/community/united-states/indianapolis-trip-report.cfm

My experience suggests that this city's attractions are not open evenings generally. My experience also suggests Indianapolis is not much of a food destination, especially compared to other cities of this size.

Re public transportation: it looks like the #37 bus runs between the Candlewood Suites Hotel (is this where you're staying?) and downtown -- half-hourly on weekdays, hourly on Saturdays, very infrequently on Sundays. The buses here aren't much ridden by commuters in my experience, mostly by poorer people, but if that doesn't bother you and you are wedded to sticking between downtown and where you're staying, I say use it. I'm not sure what the neighborhood is like there, though, so take that into consideration as well.

Here's the bus website:

http://www.indygo.net/pages/local-service-fixed-routes

Thanks, bachslunch - I had read your excellent trip report when searching through the forums. Looks like you are the only one to have submitted a TR for Indy. Not sure I want to be using a bus system with which I am not familiar in winter weather.
Hoping for some suggestions from locals that would help me decide whether or not to rent a car. Am indeed reserved at Candlewood Suites. Not absolutely wedded to this property but it is convenient to the meetings and gets good reviews and offers Priority Club points which I collect.

Candlewood is on the outskirts of downtown, and unless you're really up for walking off dinner, you'll need a car or have to take taxis (or the hotel might offer shuttle service). If you could stay on the east side of IUPUI you'd be just a few blocks walk to most downtown sites. The Crowne Plaza, Staybridge Suites and HI Express are all much more conveniently located and no car would be necessary.

How late in Jan? Superbowl activities start as early as 1/24 if you have any interest in that.

Restaurant recs: Saffron Cafe (Moroccan), Siam Square (Thai) and Santorini (Greek, go figure), both near Fountain Square. For steak, St. Elmo's is an Indy establishment famous for their spicy shrimp cocktail. All along Massachusetts Avenue are various local restaurants: http://www.discovermassave.com And I love the Chatterbox for jazz (tiny place, you're almost on top of the musicians). Winebar? Try Tastings right near Circle Center Mall.

I'll defer to bachslunch on the review of landmarks as I've not visited most of those.

I've got to run, but if you want more info I'll try to remember to check back in. I'm a local, BTW, in case you hadn't figured that out

My folks live there so I don't have the full-tourist perspective, but:

I think you'll want a car. It is a spread-out city with a bare-bones public transporation system. Standing at the bus stop in sub-zero weather (or maybe it'll be in the 40's, who can say?) is never fun.

Restaurant and food: the Broad Ripple neighborhood has good small ethnic places; if you have some daytime free, visit City Market for lunch (huge indoor farmer's market, emporium, etc with vendors offering tasty bites). There is a McCormick and Schmick downtown. The Rathskeller has good German meals. The Melting Pot is a fun place to have fondue.

I'm a huge fan of Arnies pizza and pub-style food (try the Arnies salad), but others disagree. The toppings (like sausage, pepperoni) are ground, not sliced, and form a blanket on the pizza (thin crust, hardly any sauce, perfect cheese).

As for things to do in the evening... The Museum of Art has evening programs; Clowes Hall for concert and shows; maybe take in a basketball game at Butler or IUPUI; visit indyconcerts.com for more ideas.

OK, have changed to Staybridge Suites at 535 S West Street - thanks for the info Sidny and capxxx
Will have a rental car as I need it to get to my daily meetings. Any tips on driving?

Nothing very tricky about driving in Indy usually, though you may notice some issues related to the Super Bowl:

http://www.indystar.com/interactive/article/99999999/multimedia/111215018/guide-super-bowl-traffic

Indianpolis streets were laid out by the same guy who planned Washington D.C.: a grid with four diagonals out from the center. Like many midwestern cities, it is spread out with wide streets. Easy to get around.

That being said, you'll want to look out for Super Bowl traffic (I imagine it will be like the Indy 500, when, after the event, 4-lane highways are stopped as far as the eye can see.)