AR area has been quiet for a while, so here's a 1980 Colt Model SP1 AR-15 that I picked up a while back at the LGS. I like the retro look of the SP1, like the A1 style carry handle and sights, triangular handguard, classic three-prong flash hider, and of course the fact that they were made by Colt. There are some obvious (besides no giggle switch), and some subtle differences from an M16-A1, but these are obviously easier and far, far cheaper to acquire than an actual M16.
Colt made this model from 1963-82. You'll often see them advertised as "pre-ban", which of course is marketing gimmickry that is stating the obvious, since they were all made before the 1994-2004 Federal AWB. Basically, it means they have a lug for the M7 bayonet, which is a nice feature. The early ones (serial number: SP16xxx or earlier) are already Curio and Relic eligible.
1:12 twist chrome-lined barrel is good for M193 55gr or less bullets. The bipod is a reproduction (no markings) although the bipod case is military. The M7 bayonet is real.