2.5" Laptop hard drives are specifically designed for travel with no limitations. I travel with mine everyday. In and out of the car, client appointments, stopping at Starbucks to check email, and on and on.
It sees very heavy usage and a lot of boot ups and shut downs, (I don't travel with it in the sleep mode) and after ten years of this, with either a PowerBook or MacBook Pro, I have not had a single hard drive fail. That's a pretty good record.
In my company where we are using both PC and Mac laptops, hard drive failures are rare, and none of these are being used on the desk, they are all being used by our sales force in the field.
Over the last three years I've spent a lot of time and money on SSD's just because I could, and I wanted to see which ones worked best and fit my needs.
After a few thousand dollars spent on top of the line SSD's I can say that yes, they are indeed faster for _some_ but not all tasks one does. Boot time, apps launch faster, etc. However considering the cost, if one is on a budget, it's my opinion they are not worth it.
Perhaps in the next year or so they will not only come down in price enough to be justifiable for all.