Replacing an aging system.. better cpu for the buck?

Get a better PSU, preferrably: Antec, Zalman, PC P&C, OCZ, Corsair, or even Thermaltake (if in a 110v area add Seasonic)

CPU: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$66 (Black Edition, OC's much better 3.2GHz easy)
PSU: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$75 (OCZ, yes more expensive, but much better quality 600W)
HSF: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$15.30 Arctic Cooling Alpine64

You should be able to run EQ2 with the onboard, however I'd get a card soon.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$63 HIS 4650

Here is a budget AMD build. The budget is the constraint; better choices for any number of things are possible. Even though it is one of their lowliest models, I've never read a bad technical review on an Antec PSU. If more money is available, consider a faster, Black Edition CPU. The 790GX board has the HD3300 IGP, which is better than the HD3200 found on the 780G, and also has the new SB750.

Rosewill R222-P-BK Black Steel ATX Mid Tower Computer Case - Retail
Model #:R222-P-BK
Item #:N82E16811147095

$29.99 -$3.00 Instant $26.99
Cheap, but has a reasonable layout and decent airflow.

BIOSTAR TFORCE TA790GX3 A2+ AM2+/AM2 AMD 790GX HDMI ATX AMD Motherboard - Retail
Model #:TFORCE TA790GX3 A2+
Item #:N82E16813138129

$124.99 $124.99
HD3300 video and the Sideport memory is DDR3.

Antec Basiq BP500UB 500W ATX12V Version 2.01 Active PFC Power Supply - OEM
Model #:BP500UB
Item #:N82E16817371019

$39.99 $39.99
Cheap, but it's an Antec.

AMD Athlon 64 X2 5000+ Brisbane 2.6GHz Socket AM2 65W Dual-Core Processor Model ADO5000DOBOX - Retail
Model #:ADO5000DOBOX
Item #:N82E16819103211

$56.99 $56.99
Personally, I'd try to stretch to a Black Edition CPU, but the mobo should be upgradable all the way up to a Phenom II.

A-DATA 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model ADQVE1A16K -

Retail
Model #:ADQVE1A16K
Item #:N82E16820211066

$26.99 $26.99
Will run on the JEDEC standard 1.8V.

Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
Model #:ST3250410AS
Item #:N82E16822148262

$54.99 $54.99
Decent budget drive.

LITE-ON 20X DVD±R DVD Burner Black SATA Model iHAS120-08 - Retail
Model #:iHAS120-08
Item #:N82E16827106264

$25.99 $25.99
This Retail version will include any necessary software.

Subtotal: $356.93

If your budget has wiggle room, there will be obvious places for improvement, but if not this build will be decent for the price.

I appreciate all the input.. thanks!