Asus RT-N16

Pros: -supports HTTP, FTP, Magnet, ed2k, Torrent and NZB downloads
-new firmware adds much more functionality, removes freezing, crashing
-supports downloading directly through the user interface
-very powerful
-does not overheat

Cons: There are none.

Summary: The new firmware is 3.0.0.3.78. You can download the updated firmware from their site (Asus.com). The old one was really unstable; since the new one was released most of the other reviews are invalid.

Basically, after the update the router works like a charm.
I believe this is the best router currently available for purchase.

Updated on Jan 4, 2012

The 3.0.0.3.78 firmware update also added support for IPv6 (with tunneling or native), a 3G/WiMax modem (with a special "use 3G modem only when WAN is down" feature).
The firewall component has got a DoS (denial-of-service) protection function.
There is also a VPS server integrated; you can get a free DDNS name for life.

I should also mention this:
I quote Dong Ngo (the CNET employee who reviewed this router): "The bad: /.../ Its USB ports don't provide enough power for bus-powered portable hard drives."
They do provide enough power. I have two Verbatim Store 'n' Go bus-powered portable hard drives connected to the router and everything works flawlessly.