ALI is NOT worth it in that situation.
Downgrade the PSU as 700w is OVERKILL for ANY single GPU. I would get a Corsair HX620 for that price or you could get 550w PSU or something instead. The Gamestream's rails aren't very stable either but they do have 4 of them so it makes up.
I never liked the Thermaltake Soprano as it does look nice but there are quite a few cases better for the money as there actually isn't much room inside the case. However it will work well enough I guess if you have your mind set on it.
OCZ ram isn't BAD but there are chips Sticks that are much faster than them at the exact same price. Ask anyone and they will tell you G.skill HZ's are the way to go. As everyone else said 4GB is OVERKILL. 2GB is plenty even for vista and gaming. Get one set of these.
Newegg.com - G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail
EDIT: With only a 19 inch monitor the 320 is plenty good enough. If you plan on upgrading that card within the next year again when more memory starts to matter, save yourself some money and stay with the 320.
As long as you aren't doing any kind of visual design or something then 2GB should be enough in XP. Vista you would want more but Vista also is very bad for games and programs right now and by the time you would want to even put vista on, you would be due for an upgrade I think. Vista looks and sounds great until you learn how many games won't even install on it or run. Certain programs also have a problem with it as well.