Problem with AGP is pricing. When you step down in performance, you don't save a lot of cash. Example: HD 4650 down to a 3650 saves you roughly $10. Stepping down to a GDDR2 X1650 pro saves another $10 or so. Hard to spend $60 for one of those if a much better 4650 is $80.
Keep an eye on the memory type/clocks as they do vary. Better to have 512MB of higher clocked GDDR3 than 1GB of low clocked GDDR2.
There isn't much out there new below the X1650 pro that is a step up from your card. Avoid the Geforce FX5x00, 6200, or Radeon 9550... they are below your card.
Depending on your system specs, you may not find the 3850 worth the $95.
What is the CPU and power supply?