Daily and weekly time slices

I wanted to write a short post on the topic of time management, mainly asking a question as opposed to providing an answer. I'm curious to learn how readers manage their busy schedules and what time slicing method works for them.

By "time slicing," I'm referring to two opposing methods that I've considered for time management:

1. Intra-day/small slices: Each day is filled with many types of activities that you need to be involved in. This means everyday you exercise, meet with customers, network with colleagues, do informational interviews, recruit, write code, do online marketing, eat, have fun, and sleep. That's a ton to fit in to one day, and each slice is necessarily small (or non-existent on certain days).
2. Intra-week/large slices: Separate days are devoted to separate activities. Huge swaths of time are devoted for intense focus on 1-2 important activities. For example, all coffee meetings, interviews, phone calls, etc. are on Fridays. All marketing work is on Wednesdays. Workouts are 2-3 days a week. And the rest of the days are all for intense work on ____ (fill in the blank for your most important function, like coding, recruiting, designing, etc.).

There are clearly pros and cons to each method. Large slices allow more intense focus and less switching costs. Small slices allow more "balance" in each day and quicker responses to opportunities that come up (like for phone calls, meetings, etc.). And sometimes you don't have a choice: if you really need to meet with someone who can only meet on a day that's not your "meeting day," it will disrupt your rhythm.

This decision also gets into the need to say no to various requests for help or meeting (or at least delays if not no's), which can often be painful to do.

What do you do? What methods have you found useful in managing your time along this axis?