Looking for the most cost efficient upgrade.

[Poochie]

Here's what I've got.

Athlon XP 2400+
Abit AN7
768MB Kingston PC2700
ATi Radeon 9800 Pro 128MB
WD 120GB

Now here's my situation...
I have pretty limited cash, so every upgrade I make, I want it to last.

1. My mom's computer is going to need a new motherboard because it has been giving me a lot of problems. Because of this, I was thinking I should get a new motherboard/CPU combo, but the best deal I could find in my price range was a P4 3.0Ghz with a generic PT800 or a socket 754 3200+ with some VIA motherboard (P4 is $170, AMD is $220). I figured I could use the new mobo/CPU and give Mom my old hardware. The problems are, I'd be using PC2700 RAM with a faster CPU, and I'm not sure if I would notice much of a change going from a 2400+ to the 3.0GHz range.

2. SO, I next decided to look at graphics cards. For the same price as the above option, I was thinking of getting an Nvidia 6800 128MB. This would allow me to give my brother my 9800, and give my brother's ti4200 to my sister... So it knocks out three birds with one stone. I could always buy my mom a cheap motherboard to replace her current one. The only problem is, I don't game much on my computer considering how much total time I spend on it. I've basically ruled out this idea because I think it would get the least use... Although it would speed up my games dramatically.

3. Fry's Outpost has a gig of Kingston HyperX (PC3200) for $90. If I'm eventually going to upgrade my processor I'll want faster RAM, and maybe it'll be nice to have this just in case.

4. Someone I was talking to commented that RAID would give general performance a good boost, but I don't know much about it. I guess I'd have to buy a second hard drive and a controller card.

Could anyone help me decide between those, or suggest a new option for me? Lately I've been trying out some video editing and I think I might make a new hobby out of it. I also do a lot of audio recording, and like I said before, ocassional gaming (Guild Wars, Fary Cry, Half Life 2, etc).
I know this is a really long post, so thanks to anyone who actually tries to help. I tend to ramble a lot.

 

[pandora's box]

1. My mom's computer is going to need a new motherboard because it has been giving me a lot of problems. Because of this, I was thinking I should get a new motherboard/CPU combo, but the best deal I could find in my price range was a P4 3.0Ghz with a generic PT800 or a socket 754 3200+ with some VIA motherboard (P4 is $170, AMD is $220). I figured I could use the new mobo/CPU and give Mom my old hardware. The problems are, I'd be using PC2700 RAM with a faster CPU, and I'm not sure if I would notice much of a change going from a 2400+ to the 3.0GHz range.

As long as you go with the 754 Socket 3200+ the PC2700RAM wont be a problem. What is the specs of your mothers computer?

2. SO, I next decided to look at graphics cards. For the same price as the above option, I was thinking of getting an Nvidia 6800 128MB. This would allow me to give my brother my 9800, and give my brother's ti4200 to my sister... So it knocks out three birds with one stone. I could always buy my mom a cheap motherboard to replace her current one. The only problem is, I don't game much on my computer considering how much total time I spend on it. I've basically ruled out this idea because I think it would get the least use... Although it would speed up my games dramatically.

You could do this, but in order for me to give you any recommendations im going to need to know what resolution you play at and if you use any AA or AF. The 9800 Pro can still play games at 1024x768 with 2xAA and 4xAF in most games.

3. Fry's Outpost has a gig of Kingston HyperX (PC3200) for $90. If I'm eventually going to upgrade my processor I'll want faster RAM, and maybe it'll be nice to have this just in case.

This is the option I would go with if you want to overclock your cpu. However, I wouldnt go with the kingston ram you listed. Choose this ram:
http://www.newegg.com/Product/Product.asp?Item=N82E16820231012
The ram overclocks very well and you should get a major performance boost. However you will more than likely need a new heatsink to go with it. Something along the lines of a Zalman 7000AlCu would do nicely.

4. Someone I was talking to commented that RAID would give general performance a good boost, but I don't know much about it. I guess I'd have to buy a second hard drive and a controller card.

I wouldn't go this route at all, your not going to see that big of a performance boost.

 

[Poochie]

Basically, I like to play at the highest detail level and resolution possible, but I rarely use AA/AF. If the game runs too slowly I usually decrease the resolution instead of the detail level.

I'm still leaning towards the first option, though I'm hesitant to go with the socket 754 motherboard because 939 is already out and will give me more upgrade headroom.
My mom's computer has an AXP 1800+ with some Epox motherboard, 512MB PC2700, and a Radeon 9700.

As for the RAM, I probably won't be doing any overclocking... Very little if any.