Personally, I try and organize my code libraries in groups of functionality.
If I'm doing a simple console or web project, I don't really want to drag all my UI library code with it. Equally, I have several UI libraries, split into things like utilities, components and animation/advance or specialty libraries.
This, for me, tends to create lots of small, very specific libraries (some which are reliant on others - many of my libraries are reliant a the same core/utility library for instance), but provides a great deal of flexibility as I can pick those libraries which are best going to support the current project without the need to drag a lot of, otherwise, useless baggage.
It does make management a little more complicated (as you need to remember where things are, but if you're careful about how you name and group them it should be okay) and may make the build process longer (depending on what build system you use).
From an execution point of view, I don't think it's going to make a massive difference (other then if you're doing things like network deployment, then size matters ;))
IMHO
It does help keep the projects to a small size, as they carry far less dead weight then if you had a small number of monolithic libraries...(this is a situation where in at work and it's a complete pain).