ad-hoc networks are horrible to use in a home setting. Performance is poor, there are many more points of failure, and it is not very secure.
if you feel your router is useless then you probably did not get around to installing tomato or dd-wrt yet
Routers are basically low powered computers.
with a proper firmware, you can get many useful functions.
I currently use my router to also run a media server, and also download torrents along with functioning as a VPN server that I can connect to when on the go or if I need to use a untrusted wifi hotspot, I can simply openvpn into my home router and have a secure connection.
In addition to all of that, I also have an external hard drive connected to it (the tomato firmware storage driver allows for the spinning down of hard drives, so I can leave that connected and perform whole disk backups using acronis true image.
The main feature I am waiting for them to add to tomato, is USB host support, kinda like what netgear uses for their routers for print sharing (the netgear print share is basically a USB host which simulates the device being directly connected to your PC, because of this, you can do things like build a poor mans slingbox by connecting an easycap to your router, then using the fios tv web remote app, VPN into your network andd watch live TV (can handle around 6MB/s of data so low bandwidth USB devices will work)
still think a router is useless