The Abit IP35 Pro mobo is an excellent choice, as Condor has already alluded to w/ his selection. This mobo can run all Intel LGA 775 socket CPU's to date-includes the 45nm series w/ just a BIOS upgrade.
I myself am currently running an Abit IP35 Pro mobo. That Gigabyte GA-P35-DS3L is a good board as well. These mobos are lower-end Intel P35 chipset-equipped units that have some high-end capabilities built in so they make very good foundations for budget-based Intel boxes that can also give you some performance options & some longer legs between the next major upgrade.
Please consider any of the Intel Core 2 Duo series of CPU's, either the Allendale's or low-end Conroe's to start off with as these CPU's have a lot of headroom as they overclock very well & do it on air cooling & are cheap.
Before you use your 430W Mad Dog PSU, I would seriously run your intended/proposed budget setup thru a PSU Wattage Calculator to make sure you got enough PSU to run in all intended configurations. Intel has a good one on their site that you can use for free. Another item of note: most of the modern mobos will have a 24-pin main connector & will require a PSU w/ the same connector. If your existing PSU has the old 20-pin main mobo connector, well you gonna need to also consider a newer PSU as well.
Most mobos these days are geared for using SATA drives ( mobos only coming out w/ 1 PATA connector-if 1 at all) & I really don't think you'll like the performance from your existing HDD w/ a CD-Rom/DVD Rom drive slaved on the same PATA headder w/ your HDD (assuming that your existing HDD is a PATA drive) so you might want to also consider at least 1 drive for your upgrade to be a SATA drive-preferrably the HDD.
Hope this helps you in some way.
