Every list, I would say no. 1000pts and less I wouldn't bother. 1500pts, I would be taking a Runesmith (or cheap Rune Lord) as the general, and then a Thane BSB. Anything around and above 2000pts most defiantly.
Thanes don't have that many strings to their bow, other than to add a few good attacks or if you want to wound block a challengeable character. So if I take a thane I make him into a bsb.
Generally you are better off with just a normal standard and spend points on runes to keep him alive, considering you cant have runes on both the banner and items. I tend to go with MRo Gromril for a 1+ save, 2x Ro Iron for a 5+ward, and Ro Cleaving to make him S5. Its bang on your maximum rune allowance but if you can afford it you should. If you have to drop the Wards. This guy comes in at 165pts off the top of my head.