Much of my mixing is in the box and the primary eq I use is the UAD Cambridge. A lot of different options in one little plugin.
One spot where I find myself using the shelving is when I'm boosting highs or cutting lows. With the highs I'll sometimes set the shelving mode so that it peaks upward (poor terminology here, I'm sure) and then tweak the Q to add a little bit more at that certain frequency that wants a little more exaggeration than the others, often 3 or 4k ish. In the low end it's sort of the opposite, I'll mildly shelf out some lows, have the peak point downward, and tweak the Q to get a little more cut in the mud range, often 250-500 hz.
I'll often use the shelving only when there's some particular frequency I want to emphasize in this manner, otherwise it's a low Q bandpass which I often use for broad boosts in the high end.
The low end rolloff filter I use the majority of the time is actually the 6dB/oct type. It's more a tone shaping than a "get the lows out" how I use it. The 6dB has a much more natural sound than the higher order type.