Well it depends on your style, Sony Vaio has really nice laptops that do come with an Blu Ray disc option, but it's really pricy. HP and Dell are consumer friendly PC companies, they build what you want them to build. They target almost all segments of home computing (surfing the web, gaming, emailing, office productivity), they're all pretty well-rounded companies that strive for consumer productivity.
Well for your comparison Intel Core Duo and AMD Turion 64, AMD Sempron isn't in the picture because Sempron is a lower end processor like the Intel Celeron.
The Intel Core brand consists of Core Solo and Core Duo, Solo meaning single core and Duo meaning dual core.
Core Solo uses the Yonah Core on a 65nm process technology, and a Yonah Core Ultra Low Voltage also on a 65nm process technology.
Core Solo models contains: T1200, T1300, T1350, T1400
Core Solo ULV models contains: U1300, U1400
Core Duo is a dual core architecture based on the 65nm process and the same "Yonah" core as Core Solo. It has Low Voltage and Ultra Low Voltage models.
Core Duo models contains: T2050, T2250, T2300, T2300E, T2400, T2500, T2600, T2700
Core Duo LV models contains: L2300, L2400, L2500
Core Duo ULV models contains: ULV U2400, ULV U2500
AMD Turion 64 uses the "Lancaster" core based on a 90nm process, dual core version of the Turion is indicated by the "X2" symbol.
Turion 64 25w model contains: MT-28, MT-30, MT-32, MT-34, MT-37, MT-40; 35w models: ML-28, ML-30, ML-32, ML-34, ML-37, ML-40, ML-42, ML-44.
Turion X2 64 35w model contains: TL-50, TL-50, TL-52, TL-52, TL-56, TL-56, TL-60.
Check the processor specifications before you buy to make sure you are getting enough power for your everyday needs. For me, I like the Intel Core processors but it's up to you when you buy a laptop. Also look for at least 1GB of memory, and a 60GB hard drive.
You should hold off on the Blu Ray disc until it has been well adopted in the future like how DVDs are now. It's very expensive to get a laptop with Blu Ray on and it does cost you a hefty price for the new technology you want. But hold off on it if you can.
Most laptops will come with some kind of cable knot, for your cable lock. All the hardware is not easy to steal unless you have the right type of screwdriver handy to take a hard drive.
About your shock protection, few notebooks today have that feature, since notebooks are portable and should be able to withstand drops and falls, but most aren't. Panasonic makes some notebooks that are shock proof and water proof but i'm not sure if it really does a great job, you might want to check it out first, do some research and find reveiws of what other people thinks about that particular product.