I feel the Toledo core offers the best in modern dual core technology. There is a substantive difference in terms of clock speed and cache. However, both are really good performers, both when overclocked and at their regular stock levels. It all comes down to your budget which from what we can see, can clearly support it. There is a significant performance gain by using this CPU depending on what you do, ie video editing, encoding/decoding, etc. For me, that's what I would buy: Athlon64 4400+ Toledo X2. Some people say a 6% increase in performance doesn't make up for the higher price of the Toldeo cores, but I say it does. Again, it's what you are willing to pay.
As for the motherboard not having the monitor port, it doesn't have integrated graphics controller on there. That is why I chose that 7800GTX video card for you. It's real nice and you will be able to play ANY and ALL games on there. Plus, that motherboard has another graphic port slot for ANOTHER video card if you want more power in the future. To speed it up further, each graphic port slot utlizes full 16x bandwidth on each channel and in theory will give you 32x max which is way more than any motherboard I have seen. It is a bit on the expensive side though, but it's got a rare feature that no other boards have. That rig will basically be future proof big time. Just add a little bit here and there and you'll have more power than any of us here. It's a bit of an extreme setup but it fits within your budget.
Now if you want to go something that cost less, I can suggest any motherboards that are manufacturerd by Abit, Asus, DFI, and MSI that uses the nforce4 chipset and PCI-express. For video card, if that 7800GTX is a bit much on the pricey side, you can always step down to a 7800GT video card by eVGA. They make the absolute best video cards for gamers. Dual core CPU is very nice and it WILL take over as the ultimate CPU of the future. Multi core is in, single core is out (like the CPU I got now. It's obsolete, museum quality).
Either way you go, you will have a pretty nice system.
