System upgrade, need some wise advice

[Stigmata]

I've narrowed down my potential upgrades to sets of specs, within which I haven't been able to decide on a specific part.

Current specs:
Mobo: Asus M4A78 PLUS (AM2+/DDR2)
CPU: Athlon II X2 240e (2.8GHz)
RAM: 3GB (2x1, 2x0.5) DDR2-800
GPU: Radeon X1900XT 512MB

Future potential specs:
CPU: Phenom II X4
- 925 @2.8GHz, $180
- 955 @3.2GHz, $210 (Black Edition)
- 965 @3.4GHz, $240 (Black Edition)
RAM: 4GB DDR2-800 (as high as my mobo supports for dual-channel)
GPU: Undecided
- minimum 1GB
- overclockable, reasonably quiet heatsink
- pref DX11

I actually purchased a GTS 250 the other day (which I took back), as my first experience with Nvidia cards, and it was pretty good. I like those drivers a lot better. On the other hand, my board is Crossfire-enabled.

On the other other hand, my motherboard is only AM2+. Do I gain anything good or noticeable by upgrading to AM3? Is DDR3 that much better? Do AM3 processors take a performance hit in AM2+ slots?

[edit] I picked a good time to upgrade - I just experienced a crash-to-boot during which BIOS took 3 seconds to detect my hard drive.

 

[Stigmata]

y'all jerks! I settled on this:

Phenom II X4 955 3.2GHz BE
Gigabyte GTX460 768MB
1TB WD Caviar Black 64MB HDD

Currently full-formatting my second petition, and it's taking forever.

 

[VirusType2]

Didn't even see the thread. Actually I was asleep the entire time, so it would be really freaky if I did see it.

 

[Quixoticism]

I never saw this one either.(until now)

I think the choices you made were good for what you had. The 460 is a great card! I wouldn't mind having one. And the X4 should give you enough power so it's not bottlenecked.

 

[Warped]

just got the 1GB version of that card and its godly! I can play Metro 2033 in glorious 1080p in Direct X11 on a 5 year old rig with it looking as smooth as butter on my 23" monitor

 

[Stigmata]

It really does run fantastically. I'm just putting the finishing touches on installing something like 60 mods for New Vegas, and a lot of them are for textures and shaders to see how far I can push this system. I already ran vanilla NV for about forty seconds on max settings and it was smooth as a baby's va.... bum.

 

[YROC]

The 965 didn't cost anywhere near $240 for me. The hell.

 

[Stigmata]

I dunno, it was expensive on the website but once I got to the store they were back near newegg prices. Makes no sense.