Well... It's not the best lappy I've ever looked at, but I guess it depends on what you want it for. If you are just going to be doing word proccesing, email and internet browsing, I'm fairly certain it will be ok.
However, I am also concerned about the "longevity". 512 MB of RAM is going to be (if already not) obsolete here soon. 1 GB will be the norm, and you will be lacking in that department.
Also, the hard drive is decent. Not 7200 RPM, but you won't notice too much of a difference. Again, depending on what you are using the lappy for, 80 GB might be too small. If you want to use it for a long period of time like you say you want to, I would suggest at least a 120 GB.
Also, if you are worried about battery life, you can always pick up an extra spare battery.
Finally, the processor is getting outdated too. Core 2 Duo's are also soon going to be the norm, and this lappy will be lacking in this department as well.
I am not familiar with CAD, but I'm sure you can find a better deal than this one.
Sorry to burst your bubble...
Take a look at a few of these:
HP Compaq 530 Notebook PC - Intel Centrino Core Duo T2050 1.6GHz, 802.11abg Wireless, 1GB DDR2, 80GB HDD, DVD RW, 15.4" WXGA, Windows Vista Business GH641AT#ABA in Canada at TigerDirect.ca
Acer TravelMate 4200 4297 Laptop PC - Intel Centrino Core Duo T2250 1.73GHz, 802.11abg Wireless, 1GB DDR2, 120GB HDD, Dual Layer DVD RW, 15.4" WXGA, Windows XP Professional LX.THB06.132 in Canada at TigerDirect.ca
Acer Aspire AS5610-4693 Intel Centrino Core Duo T2050 1.6GHz 802.11abg Wireless 512MB DDR2 120GB HDD Dual Layer DVD±RW 15.4" WXGA Windows® Vista™ Home Basic Notebook PC LX.AY10Y.003 in Canada at TigerDirect.ca
If you have anymore questions, feel free!