Hey! So you have already started! Great!

I can feel de excitement going on…
The Intel Lemont DP965LTCK seems to be a good choice, it has pretty everything you may need for a long time.
The processor, I don’t agree. I was after the exact same one, but in a “cheaper” range, you have a bigger and more powerful CPU, that is the one I’ve got, the E6750. Intel is moving toward the 1333MHZ, so they push people to get the 6750 instate of the 6600, but it is a better processor, for about 20 dollar less!
You should really read the reviews around and so you can see that for yourself.
About the Corsair VS2GBKIT667D2 DDR2 KIT 2X1GB 667MHZ CL5, I have to say that I was thinking on getting 667 too, but I was wrong. I have speculated much, read much about the subject of which is better, the 667 or the 800. The truth is that the performance difference it is important, depending on the kind of programs you’re going to use. For me for instance, using multimedia apps, it makes an important difference, because may programs uses ram in a particular way that 800 is much better than 667. I cannot explain you in depth about it, because it is too complex for me, but I don’t need to know everything to know what is convenient for me, because I try things out before, so think about it. Read reviews and give some readings to the way your programs will work with respect to ram, and then decide. Ram is something you cannot save money on; it is like your legs… way too important.
Nothing to say about the ASUS EN7300GT because I don’t know it, but I guess that if you don’t do graphics at all in your machine, it will be plenty for what I have read.
About the Western Digital Caviar SE16 320GB SATAII, Western Digital Caviar Se 160GB 7200 SATA, of course, great choices, but there, if you can, spend some more money and get the biggest drives you can afford, you’ll need them sooner or later, rather sooner… it is always like that.
The Antec Titan 650 is a great choice, but a bit expensive perhaps… Well, anyway, you know, when you do a PC yourself you’ll truly love to have lots of space to move, and this implements keeping everything cool as airflow gets moving much more than in small, bad quality cases.
What you don’t mention is the PSU, unless you are getting the 600 watts that comes included with the Antec, Titan 650. If this is the case, you’ll get a BIG PSU. Do you need it really? If you plan to plug many more things in the future, it’s ok, otherwise it is a waste of money in both ways, the first, the price of the PSU, the second, electricity bills. I think that with a 500watts high quality PSU you’ll get an over-killing power supply. When you get a PSU, you better get the best possible make, but not necessarily the biggest in power. You should also investigate that the PSU it is proven to be SILENT, or you’re going to suffer from his bothering sound for years to come… Get to read the reviews of every item you intend to buy, always. Do it with the PSU too, so you get the “real thing”.
I don’t think you have any incompatibility there. But, it would be good to know how many SCOPE cards are you planning to install?