For my 24x7 PC, I have an old desktop running ClarkConnect v4.3. It acts as both broadband gateway and torrent client (Torrentflux). It's basically a P4-2Ghz with an Intel board, 512MB DDR, 500GB HDD, and two NICs. All the wireless "routers" I've tried so far (D-Link, Linksys and TP-Link) are either unreliable (requires a reboot every few days) or lacks the features I want in a broadband router (ie. IPS/IDS, bandwidth control, advanced firewall configs, VPN, Windows file sharing, web and FTP server, etc.)
The only thing the wireless routers are good at are doing switching and wireless AP roles. I currently have two TP-Link wireless routers working as such. The D-Link wireless router (DI-624+) is hopeless, as even the wireless portion of it keeps shutting down for no apparent reason. It's been replaced 3x and already running the latest firmware... pure CP\@p...
I will eventually add more HDD capacity to this in the future so that I can stream videos directly from it. With the current setup, I have to regularly move downloaded files to my main PC or HTPC before the 500GB clogs up.