How long does it take to download the blockchain? It's been over a day and still going
You probably don't want to download the blockchain

The blockchain currently weighs in at about 144 GB (check current size) 
Assuming you have solid 2 megabytes per second download speed, it would take around 20 hours just to download them. 
In practice, this takes much longer, as your computer will verify every block individually, which takes some time.

Also, if you're not doing any mining, it may be wise to look into a lightweight client such as MultiBit or Electrum.