I prefer to keep it simple to clean, safe for the beardie, sanitary (comes from being simple to clean which then helps it be safe for beardie - fewer places to breed bacteria, parasites, etc), and somewhat natural or nice looking...
A roll of cheap brown masking paper from the local hardware store is what I'm using now - topped with a handful of natural looking flagstones (flat landscaping rocks). The paper is just an inch wider than my tank, and I cut to length. Should last a year or more for just a buck fifty or so.
Most poos end up on a rock that I just pick up and wash here and there. Every few weeks (unless there is a mess) I change the paper.
I like to avoid wood products (harder to clean). My hides and climbs are rock. Natural stones are good at keeping the nails trim.
I've also had good luck with reptile carpet. Some don't like it, but I had no issues.
Some people just use paper towels, others news paper. Works fine. Just don't shred it up...
Tiling is probably the most common and best long term solution. For now, I'm sticking with a 40gal breeder tank and the paper + rocks. But at some point I will be building my own and will use tile more than likely.