Hi, I feel your pain. I had the same situation with FIOS. We have 4 TV's, which meant we had to rent at least 4 cable boxes from Verizon, if we wanted a DVR, then we would have had to rent that too.
I, and many more on the now defunked thegreenbutton.com website, solved it by setting up an HTPC, running Windows Media Center built into every copy of Windows 7 with a Ceton InifiniTV4 Tuner with a CableCard from the provider. Using media extenders over the home network we have been able to bsically turn every TV in the house to a DVR with centralized virtually unlimited storage, and only have to pay $3.99/month for the CableCard rental.
CableCard from the provider allows you to unlock everything you subscribe to, uncluding the highly encrypted HBO and Cinemax.
If you have a digital movie or music collection, you can integrate it into Windows Media Center, along with Hulu and youtube, and whatever other internet TV service you would like.
The savings from not having to rent boxes for every TV in the house pay for the system in about a year. Plus, you have the ability to Watch, Pause, Record, Rewind live TV from any room in the house. It also gives you the ability to pause in one room, and continue watching in another.
6 TV's in the house on FiOS and we only pay $4.99/month to connect them all!!! Power to the CableCard and WMC7!!!