Be careful what you buy. Some of the ones that have agp and pci-e slots for graphics cards actually only have a pci-e slot and an AGR slot. These agr slots are not true agp slots and you will take a considerable performance hit, thats if you have an agp card thats compatiable with it in the first place as they only support certain cards, a list of which is usually on the manufacturers website.
The only mobo's that have a proper agp slot as well as a pci-e slot are the ones with a ULI (i think its ULI) chipset but i have no experience of these boards so cannot say what the performance is like.
If you are not interested in pci-e slots for your graphics card and you want to keep using your agp card then i can heartily reccommend the MSI K8N Neo Platinum. It is an excellent motherboard and uses the Nforce 3 250Gb chipset. I had one (still got it actually) before i did my upgrade. It has 3 ram slots so you can fit up to 3 1gb sticks, 5 pci slots, so you are ok there, an 8x agp graphics card slot, up to 8 USB 2.0 ports, 4 sata ports and a realtek 7.1 onboard sound processor. It also has the bonus of a passive chipset cooler. Overall a very good motherboard and comes with loads of cables, a usb 4 port backplate and an excellent manual.