Since I'm a sucker for a bargain, I picked this library up from the "clearance sale" part of the website for $19.95 - last I checked, they were still available. This is a real bargain - it's always great to get well-programmed libraries that don't require much tweaking to sound great.
This library is in AKAI format and translated very well via Chicken Systems Translator OS X. I'm usually very leery of guitar libraries but I think this one will prove to be very useful, as it features a huge number of guitars and basses--both acoustic and electric. All of the sounds have loads of character, and don't need much in the way of effects, although they sound great bussed to your favorite effects plug-in.
I should mention that you'll want to lower the default velocity offset, as they have most patches set to +15 or something like that. This is easily done on the front page of the EXS24 interface. On some patches I actually went the other direction (-10 etc), because you don't want to lose the first layer of 3 or 4 layer programs. Along with this, you may want to "compress" the velocity sensitivity using the adjusters on the right hand side - especially for electric bass and guitar which don't need to have a huge dynamic range, and you'll want the multiple layers to be the same or similar volume levels in order to create convincing lines.