Where to buy transformers and adaptor plugs in the US

My mom is planning on getting me some transformers and adaptor plugs for Christmas.  She was gonna get me a travel one, but I stopped her.  Where can one buy good transformers in the US?  I searched all these posts, but it looked like the websites listed were for UK sites, and didn't include any US sites (it makes sense though!)
Thanks

A lot will depend upon what size transformer(s) you need.  A few small ones up to 100 watts each, or a large 3kW one, for example? 

You'll find some in the mail-order catalogs, but quite often those sold in the U.S. will be supplied with a European plug, not a British plug, so you'll either need to add a plug adapter or cut-off the European plug and replace it with a British one when you arrive.

All Electronics in Van Nuys, CA is one example which has an assortment of sizes, although note that many of the smaller types are not suitable for American appliances with a grounding-type (3 prong) plug:

http://www.allelectronics.com/cgi-bin/category/790970/Voltage_Coverters.html

Thanks Paul!
I just want to use them for my kitchen aid mixer and food processor, that's it.  Everything else, I am getting rid of and buying in the UK. 

Radio Shack is the most convenient.  Some Best Buys will have them as well.

If they are out west they can consider Fry's Electronics.  They have everything (literally).

Is this any use?

http://talk.uk-yankee.com/index.php?topic=39335.0

Vicky

Thanks!