Welcome to the forum!
Typically, you choose speakers first and then worry about a receiver or amp to power them, but since you have the 3808, it should power pretty much anything. Speakers are incredibly subjective so it wouldn't be wise to go on someone's recommendation alone. Get out and audition some of the usual suspects like Bostons, B&W, PSB, Mirage, KEF, Paradigm, DefTech, Monitor Audio, to name just a few. Bring your own music, take your time, and take some notes. Also, HSU makes excellent subs so I'd give them a look as well as SVS for subs. You're safe buying HSU or SVS subs without auditioning as no one will tell you they suck.