When describing a series of actions or steps to be performed: What is the thought process that 'tips the scale' in one direction or the other, when trying decide if it is a process or a method?
There are actually only two claim categories, you either claim a physical entity (product, apparatus) or a physical activity (method, process, use), as outlined in decision G 2/88 of the Enlarged Board of Appeals of the EPO. You can find it here: http://www.epo.org/law-practice/case-law-appeals/eba/number.html
In my field (chemistry) we usually claim a process for preparing a chemical compound. But we also claim a method of preparation of a chemical compound. The scope of the claim is pretty much the same, as you can imagine, but the expression "process" is shorter that "method of preparation" and thus sounds more elegant. You really want to draft claims with as much less words as possible!
And I have not see any examiners either in EPO (Europe) or in the US objecting about a using the word method vs process. I would dare to say that it mainly depends on the technical field in combination with adequate knowledge of the (English here) language.
I may be missing something, but I am not sure why this would matter? Both process and method claims would fall under the statutory (35 USC 101) category of "process".
The only place it would seem to matter is w.r.t. to "product by process" claims as DonQuiKong points out. In this case, you would not be claiming the method/process, but the physical outcome as defined by the method/process, and thus this sort of claim would probably fall under the statutory category of "composition of matter" or "manufacture".