I would say any carring case will do just fine. I personally have two Targus bags.
If you own a TiBook, and you frequently work at a desk I would recommend the PodiumPad (Here ) for added heat dispertion. In addition, the PodiumPod will place the TiBook at better typing and display angles. Mine works great; I use it everyday.
You might want to check this new product out. It's called the Googie SmartLap (Here ) and it might be worth loooking at. It looks like it would work great if you use a external keyboard/mouse set-up.
The most usefull thing for me (pismo, but shouldn't be too much different) is this little neoprene sleeve from case logic. IT just hold the book, but for short jaunts or when you can stash the cords and all in other lugage, its great. It protects the computer, but leaves it this enough to slip into a back pack or a briefcase.
i would go for that laptop sleeve, personally, but i have my Ti on order and haven't had any field experience. but it looks like the perfect bag--little bigger than the laptop itself, with a little room for a few accessories. mostly just the essentials. it just depends on how you plan to carry your laptop, though.