Cisco's interactive catalog is an amazing way to see and 'touch' the entire portfolio. Built by Kaon, a former gaming company turned marketing company, has won many awards for their ability to digitize accurate reproductions or models in 3D.
Check out eBrahma's sample certification exams for Cisco, Microsoft, Juniper and ITIL. While these exams are not as comprehensive as paid sample exams, they provide a great baseline for topic knowledge.
Steve Winwood wrote a great blog post regarding how to download Cisco Live on demand content for offline viewing.
The Cisco Meraki WAP is the gold standard for corporate-grade wifi. The integration and application support are excellent.
Cisco CNA 5.0 & Cisco CCP 2.7
While I wouldn't mind specializing doing Cisco-only work, I am not Cisco certified (officially) and therefore should not be listened-to regarding the following. I'm surprised how many Cisco certified professionals I work with have ever used CNA or CCP. Both programs are free, by the way. The CNA shows all corners of the device displaying tons of information, a lot of which real-time. The CCP lets you create config file templates. The really neat thing about CCP is if you don't know syntax, you can set the option in the GUI and copy the output, very helpful.
My first experience with Cisco UCS chassis and blade servers was a memorable one. Virtualization is new to most Cisco engineers it seems because managing the UCS firmware is almost always performed incorrectly and is the cause for various communication, application, overall server performance issues. UCS produces a central status report showing green and red lights regarding system health. This can be used to quickly identify firmware mismatches which is the most common cause of PSOD (purple screen of death) hit to the hypervisor.