I have a similar set up. However, before getting my ATV3, I had gotten a
ZyXEL 300 Mbps Wireless N Access Point, Ethernet Client, Universal Repeater, and Range Extender (WAP3205) to use as a wireless Ethernet bridge to my TV. It's about 1/2 the price of the ATV, but it is only a bridge--no subscription service, etc.
Having said that, the ATV is amazing! The only shortcoming is that it doesn't offer Hulu Plus service at this time. The upside is that you will be able to access services through your iPhone and mirror them to your TV through your ATV--and you can get app on your iPhone. (Lastly, you WILL eventually succumb and get the ATV.)
Hope that helps your decision.
(BTW, I did not hook the ZyXEL directly to my Sony Bravia, but to my Sony Blu-ray player.)
Message was edited by: JettaRed Added comment re: hook-up to Blu-ray player.
Another option I prefer to wi-fi is using mains powerline network adapters such as those made by Devolo.
Belkin, Netgear etc also have versions of these.
One other thing, AppleTV cannot provide an ethernet connection to the TV when connected via wifi to your network.