No...  SPL isn't always a good measure either... as percieved volume can change depending on whats playing and the situation.

Some things just will never change...The physics of your monitor and the interaction of your tone in your situation is something only you can balance...

The same old fundementals of leveling a POD apply mostly like they always have...get the tone, leave room on the channel volume and use the channel volume to balance...If you used an SPL meter to ballpark the level and it worked for you...I don't see why it would not work again...But like Zap stated, a meter alone isn't really going to do it...It's one measure and not a bad one to have...but there is more complexity...

There is some addtional control with the mixer that are new and if you are using a tube amp or a DT then the channel volume can actually play into the tone more than it did in the past...

I like Jim's suggestion of using the looper...I use that quite a bit to check patch levels...But like Jim mentioned, the acid test is the real situation and little tweaks are almost always needed...

Many use this trick that should get it into ballpark territory. Hook up the pod to a mixer and using both headphones or some form of monitoring devise. Using the PFL, or input metering on the mixer, set each patch for a standard setting that is the same for each patch. You can while listening to your monitor dial in the volume for the percieved level. The metering will get you really close and listening should finish it up.

The one thing I have found is that the dirty patches will sound very close to the same when the meter says they are the same. The clean patches will usually need a bump in level to equal the output of the dirty patches. The compression that occurs when distortion is created increses average output volume even though in reality it's not producing a whole lot of volume. Dirty channels can be set to a standard 0 and the cleans will usually need to be pushed further to level out volume wise.