Passed SNRS 642-504 yesterday with 953 score, not bad....
For self-study i used the Student Guide but this is lacking in some areas compared to the exam blue print;
* IPS V5 signatures
* GET VPN
* DMVPN
* High Avail IPsec
* FPM
for these you can find numerous pdf's on cisco website, some of them very interesting...
Did watch the CBT for the old exam, i would say its not really helpful for the exam but more as a refresher and a laugh with Jeremy. ZFW is covered in 2 CBTs from the CCNA_Security exam.
When it comes to hardware, Ive got a 2611Xm for IOS FW which im using on my internet connection and a c3550 plus GNS of course.
Just got a ASA 5505 off ebay so when that arrives on with SNAF !!! Thinking of also getting a PIX 506E or 515E depending on how cheap i can source them. Good to get familiar with the old too (as there still so many around...)