That's my issue as well, I don't like a lot of MyBB's themes.
So what I did was I found the most "basic" custom theme out there that I could find (and free), and customized it like crazy.
I highly recommend anyone to do that, even if they don't know how.
I started the same way. Of course I still don't know everything, considering I don't know how to make themes from scratch, but it's a very useful skill to be able to manipulate the code & graphics to what your needs are.
I used DeviantArt for photoshop guides, and MyBB.com's forum database as the knowledge-base for finding the answers I needed.
I don't understand why everyone is so against myBB. Apart from the installation its a very friendly software and even if there aren't many good themes available there are coders who do great myBB themes for free.
I agree with Tindris. MyBB is not bad at all. In fact I have found several interesting themes for it from way back before; too bad I didn't keep the link to show you. You might just haven't yet looked at the right place. There are some graphic design sites which offer free premium MyBB template and they look great.
Getting back on topic, what kind of help do you want, Krymzn? If it is about appearance, then I suggest you not to give up very quickly and keep on searching until you find the one you want. Or get it customized. For the rest, I think MyBB is easy to control and to use so you shouldn't have any problem. Even installing plugins is easy. ^^
Well, ive always hated on mybb themes, i have seen 1 good theme that would be decent enough to use on a Tech/Webmaster related forum. Some of the paid software allow you to use any decent theme in there dtatabase.