AGP Graphics cards, still worth it?

It may, for "old" cards, at least.

Tom's hardware has dug in deep into AGP and old rigs to take a look at AMD's new AGP offer, the Radeon 4650 AGP card.

The benchmarks speak for themselves, the Radeon HD 4650 is not the card to choose for AGP motherboards. The 2.6GHz processor is an overclocked AM2 X2 4200+ one, coupled with DDR2, while the 2.0GHz processor is a socket 939 Athlon 64 X2 3800+, using DDR memory:

There are better cards available, namely the old Radeon HD 3850 is still a very good proposal and it's selling for around $95, considerably below the more similar HD 4670 AGP ($115) and slightly higher than the $75 that theHD 4650 costsof the.
Better PCIe cards are selling for less but, depending on what you already have, it may still be worth to upgrade.

Review @ Tom's Hardware