No BerryBuzz is a paid app.
To answer your earlier question yes wifi takes priority over 3G. If you don't wan't you wifi on all the time and want to avoid the nusance of switching on and off your wifi there is Smartwifi which uses tower tiangulation to find where your wifi hotspots are and turns it on only the these areas. This is a paid app.
If you want weather there is weathereye. (free)
For themes just look here:
BlackBerry Torch 9800 Themes - BlackBerry Forums at CrackBerry.com When you see a theme you like just copy the ota link to an email and send it to yourself and access it from your Torch to download. Makes life a bit easier than typing out every URL.
Use either google maps or waze for GPS.
POYNT for functions similar to yellowpages (addresses and phone#s)with ability to see movie listings near you with trailers, as well as weather.
Enjoy your Torch.