Cool logo. I like all the suggestions already given with regards to the drop shadow. Also remember that drop shadows don't print very well. So, if it's even half questionable on your pc screen, it'll probably look terrible printed. That is just my experience with them.
On another note. From all the design I've done in the past. You want your logo to be able to be reproduced to include your whole name. The "TK" is a great logo to put on the corner of a poster or business card or something. But, on a big poster advertising your band, you want your bands whole name headlining it. No one will know what "TK" stands for if that's all they see on the poster.
Here's some examples of effective, yet simple logo's:
http://www.lakmus.ru/design/metal.html
Your bro did a GREAT job, he's got the whole concept down. I'd say maybe do a second logo with your band's whole name with just cool typography. This will get people's attention when they see it on a poster, it will convey what the poster is about, and it will give your band a visual presence!
Those are my humble 2 cents..