These days, I would only allow 8P8C connectors to the wall. You lose too much flexibility if you ever wanted to replace your regular phones with VoIP then you're stuck with having to re-punch RJ-45s. Since GbE switches is so inexpensive, you won't be able to use it on a Cat 5 that has one of its pairs commandeered for telephone.
Ideally, each location would get at least 2 cables. 1 voice and 1 data, minimum. Which seems to work ok for residential and small business. I prefer at least 1 voice, 2 data. And often run 2/2 in a commercial setting if warranted.
Just this week I cabled a gas station/Convenience mart. Phones, Fire Alarm, Burglar Alarm, Pump Monitoring, Credit Card, Customer ATM, and FAX were all still POTS based. The POS system, Managers PC, and Security DVR were IP based. Some of that stuff is available in an IP solution, but they didn't choose that route for whatever reason.
I like the idea of completely modular cabling systems. But for many deployments it would require a huge number of "drops". You end up with a bunch of 8P8C cables serving nothing but 2C devices. One 4 pair cable can serve 4 POTS devices.
here's one cable split to 3 devices at the Managers desk. So, 3 cables instead of 5. The security guys slipped in behind me and added cables to my location, so I had to get creative with the faceplate...