I hope I don't dredge up the ire of our members, but I've used a glue gun to hold down Clark boards... it won't come lose, has a tiny bit of vibration reduction, and will peel right off if you need to :P

Magnets are awesome to hold hulls together and it's usually the first thing someone will do on a HL tank!

I've also ordered a buttload *a buttload is about 475 litres, look it up* of M3 nylon standoffs.. Ive recently found them incredibly useful for mounting just about everything else.