I have been on a Stainless Steel bottle buying kick, trying to move away from plastics. When I do something I tend to do it in a big way, or as some may say over do it in a big way. In addition to a couple of Kleen Kanteens I already own, I just bought a couple new Sigg bottles, as well as a neoprene holder to help insulate when carrying hot or cold tea. Admittedly the bottles above are more for water while working out or daily travels, but the addition of the neoprene holder makes them versatile for taking along hot or cold tea also.
Insulated Stainless Steel Bottles:
I just recently bought TWO. One is from FlyLady.net, that I saw in action when dotK came to visit me. http://www.flylady.net/pages/FlyShop_swb.asp
This is a 16 oz double insulated bottle that dotK takes everywhere and I really felt I had to have one after her visit. It easily accommodates large ice cubes and has an easy to drink from top. I have used it a couple times already and this will for sure be my go to bottle for taking teas along this summer. My current one is glass and although I do love seeing the color of the tea, it pretty much scares me to travel with it. In fact to the point of putting rubber bands on as grips, and still thinking someday the worst may happen.
Insulated Stainless Steel BREWING Bottles:
I have not really seen the advantage or need of brewing on the go. But I know many ask or seek out travel containers to brew and take. For me, I'd rather brew at home and take along. But feeling like I might be missing something, or that I may need to brew while traveling I bought an insulated brewing/travel bottle by
http://pure-hydration.com/
I have not tried it out yet, but the brewing basket looks small for the bottle size and will likely make a mess. I guess you hold it upside down as you brew? Which means leaves and pieces will have to be washed or wiped out of the ATTACHED cap. This bottle does have a large mouth for ice and I also like the ice cube filter screen that keeps ice from blocking the water flow as you drink. Overall it's a nice insulated bottle and comes in 3 sizes.
And now - now that I bought all those, NM Tea Company introduces a very nice looking Tea Tumbler with Infuser:
http://www.nmteaco.com/Tea-Tumbler-with ... p_401.html
This looks to be a very versatile size and may just be what many of you are looking for in something that is insulated for travel. Even w/o the infuser this is a nice size travel container. If I had not just bought out all the bottles on eBay

*Edited - 05/30/09 11:12 PM PST* I inadvertently was calling these bottles aluminum, when they are actually stainless steel. Good catch Ebtoulson! MarshalN - I apologize for the error. It should be noted all the above which were referred to as aluminum have been corrected by this edit to read Stainless Steel. The Sigg bottles however are aluminum with a patented inner liner. - V.