Got my new bike built last week and rode it on Saturday.
I'm rather pleased with it. Took it out for 72km of trails, gravel tracks, "brown lanes" (tarmac covered in leave litter and mud) and tarmac. It was great on all of them.
I built it to a budget and used what I had in the spares bin where I could.
Frame + Fork - 18in Surly Karate Monkey
Headset - Dia Comp Rasta
Stem - Cheap On-One
Bar - Race face Atlas (785mm)
Grips - Pedros Dice Vice
Post - Thomson (I have a dropper post that will fit)
Saddle - Madison Flux
Wheelset - Superstar Hubs with Pacenti DL31 Rims
Tyres - Cheap Conti X-Kings
Go Bits - Mix of Deore and SLX (2x10 with Bash)
Stop Bits - Cheap Shimano M395