It all depends on the use of the system. Office apps vs. games. Whether or not you plan on overclocking.
Either of those PSU should be fine.
If you are not planning on OC'ing I'd say the E6600. 4MB cache and higher stock speed.
I'd go with 2GB of memory, 800 if you can. This has worked great for me so far, not the fastest but priced right for me.
As far as video, if you aren't gaming then the 7600 is fine, but if you are then I'd recomend the X1950 Pro or wait till DX10 cards come down in price a bit.
First any thing available locally? Saves a ton on shipping. Lots of good 19" monitor out there. Viewsonic comes to mind.
For what you are doing I think the 7600 or a x1600 would be fine. Only gamers really push the GPU enough to go higher.
...I hope everyone saw my post which says that although I don't play many games, I heavily use CAD programs like SolidWorks and CATIA.
Yes, but very few of us do. Thus, any video card suggestions you get are likely to be game-oriented, not CAD-oriented. You might try asking around some CAD forums for a good video card for that, and (importantly) whether or not you should go 64-bit for the OS and apps. A 64-bit OS will let you use much more RAM, which may help a lot for your CAD work. On the downside, not all software and hardware is compatible with a 64-bit OS.
Yes, 2 gigs of 667 RAM is FAR BETTER than 1 gig of 800.
I live in Canada, so I'm not entirely current on the 6300 vs 6600 pricing, you'd have to check.
I used to do ALOT of CAD....still do some. A 7600GT handles it no problem. Unless you're doing super high quality 3D renders or using 3 monitors, the 7600 will do fine. In fact, most gamer graphics cards will. I know that CAD doesn't need the 3D acceleration that these cards have, so in many ways they are actually overkill. A graphics card that can easily power CAD may seriously chug in games. However, a great gamer card will normally chew up CAD with ease. I still do alot of 3D stuff and my old 7600GT did just fine. So the nice thing about that card is that it will handle both CAD and games
Samsung is better picture quality overall than Viewsonic, dollar for dollar. You don't need a 2ms refresh rate for what you're doing. So it entirely depends on your budget. Is Viewsonic bad? NO. Is Samsung better? YES. But it will also cost more too. Get a standard aspect LCD, not a 19" widescreen. If you can afford it, 2 19" monitors will be absolutely indispensible in CAD. I cannot go back to one monitor now, no way. Even look at adding a 2nd monitor later if you can. And just get 1 decent one now. And if you want another brand, believe it or not, Dell has great monitors. I believe this is because Samsung makes most of theirs