You've resurrected a very old thread, but this deserves comment:
I haven't read the second edition of Vol I, but the original was one of a kind and is still worth reading even though parts are obsolete. It's probably the best technical book I've ever read.
The second volume is a commentary on the source code and probably won't be useful unless you're building a TCP/IP stack or testing one. If you really care about the low level details however...
I think volume three is mostly obsolete.
BS in IT: Security, CISSP, CEH, EnCE. MS in progress.