I've had similar issues connecting to most WIFI hotspots, as well as my home network. I would periodically disconnect from Gtalk, and web browsing was painfully slow.

I corrected this by disabling the Power Saving features for my WIFI connections. You have to do it individually (as far as I know) for each network you connect to. It's located in the advanced options of the network connection.

Hope that helps, and yes it does seem to eat up my battery quite a bit more.