Paul, if you have a very heavy collection of tools to put in, the ball bearings may be worth it. Otherwise, slides work just fine, particularly for the smaller drawers, which can't hold enough stuff to have weight be an issue.
The best place to look is Sears because of the wide selection of styles. These are regularly on sale, so keep on eye on the Sunday circular. Also, my local Sears always has scratch and dent models on the floor, so if you don't care about such things, you can often get a more expensive model at a lower price.
I have an entry level set (wheeled lower, chest on top) from Lowes (Waterloo brand), and one of Sears mid-priced Craftsman upper chests. I use these to store ammo and reloading components (read: lots of lead). At various times, I have probably had a several hundred pounds worth of stuff stored. Never any problem.
The one thing I do like about the mid and higher priced setups is the key is usually all that's required to lock the chest, as opposed to some type of key/locking bar insert, which is harder to use. Because I keep ammo in these, the key lock without the bar is much more convenient for entry and exit.
