I'm extremely dissatisfied with the 'popular' choice for routers in homes and small offices. They are expensive (upwards of 60$), lack a great deal of useful configuration options, and seem to need to be restarted quite often. (Linksys comes to mind).
I've been on the market for a good router lately, and slowly collecting a set of requirements I feel good routers should meet.
Maximum number of TCP/IP connections. - This isn't something I see any routers advertise, but in terms of supporting torrent applications, I've been screwed by routers that support less than 20 here. From what I understand a fairly standard number is 200, but there are not so expensive routers that support thousands.
Router configuration menu - Most have standard menu's that let you set up basic things like your wireless network encryption settings, uPnP, and maybe even DMZ (demilitarized zones). An absolute requirement for me, however, are routers with good enough firmware to support:
Explicit Port forwarding
Assigning static local ips to specific mac addresses, or at least
Port forwarding by MAC address
Port, IP and MAC filtering
Dynamic DNS service for home users who want to set up a server but have a dynamic IP
Traffic shaping (ideally) - giving priority to packets from certain machines or over certain ports.
Strong wireless signal - If getting a reliable signal requires me to be so close to the router that I can connect an Ethernet cable, it's not good enough.
As many Ethernet ports as possible. - Because I want to be able to switch from console gaming to PC gaming without visiting my router.
So far, the best thing I've stumbled upon (in the bargain bin at staples) was a 20$ retail plus router. It was meant to be the cheapest alternative until I could find something better to purchase online, but I was actually blown away by the firmware capabilities. It supports defining reserved bandwidth for certain network traffic, dynamic DNS, reserving local IPs for specific MAC addresses, etc. At 2 am when my roommate is killing our Internet with their torrents, I can limit their bandwidth without outright blacklisting them.
I have, however, met serious limitations when it comes to network traffic between local machines. It claims a 300Mbps connection, but I have trouble streaming videos from my PC to my console or other laptops wirelessly. It has a meltdown and needs to be reset once in a while (no more than a couple times a month), and it's got a 200 connection limit. There 4 Ethernet ports in the back but I'm pretty sure the first doesn't work.
So some great answers to this question would be:
Any metrics you use to compare routers, and requirements you have for new candidates.
The best routers you've found for supporting home servers, file management systems, high volume torrent traffic, good price/feature ratio, etc.
Good configuration advice (aside from 'use Ethernet whenever possible')
Thanks for your feedback and experiences!