Super Shuttle doesn't run after 11:00pm. The last bus from the airport to downtown is at 12:45am. So it's either rent a car, catch the last SkyRide of the night (if your flight isn't delayed), or catch a cab. I've never taken a cab to downtown so I don't know how much it costs, but I believe it is a fixed rate.

Cab is flat rate to downtown. Its right around $45 dollars.

I might have offered to pick you up, if you didn't have that obnoxious signature :p. What is it now, 8 of the last 9 editions of The Game have gone Crimson?

A neat trick is to rent a car in town. Most major rental car places will let you drop off a the airport for no charge. It can easily be less expensive than a cab for the return.

Going to Denver for the Rockies home opener my plane lands at 9:55 and the game starts 1:15 which way would get me downtown to my hotel the quickest and cheapest?

Best bang for your buck is probably the super shuttle. Cost you 20 and will drop you at the hotel. Takes about 45-min as its a shared shuttle.

Cheapest way is the Skyride (bus), Denver RTD. Its 8 bucks and will drop you at the bus station. With a 10am landing though, you may be waiting a while by the time you get through the airport. Takes about an hour to drop you at Market Station, right downtown, couple of blocks from coors field. Bus takes about an hour.

The airport isn't that far from downtown, you'll have plenty of time to get to your hotel and the game.

As this thread has stuck around, some of the prices have increased:

RTD Skyride to downtown is now $10. Service is hourly except during the morning and evening rush

Flat rate taxi from the airport to downtown is $55. Flat rate from downtown to the airport is $51. There should be no additional charges for people or baggage. Make sure they run it flat rate as the meter rate would be $65+ depending on traffic. If the meter comes on at all, make sure to ask about the flat rate. The flat rate boundaries are posted on a sticker inside every cab. There are also higher flat rates to Boulder, Broomfield, and the Tech Center.

I believe Supershuttle is $21. However, as it circles the loop of downtown hotels you could end up spending a lot of time in the van. That said, you can wait in front of a major hotel downtown and the Supershuttle is by every 15 minutes. In the same lane as a Supershuttle, during peak times, you can usually find some unmarked white vans that can negotiate rates. I once got a private ride to the tech center area for $35 and downtown for $40+tip.

the AF skyride to downtown is now 11$... and if you get on first theres a row with extra legroom like the bus bulkhead :D