I wasn't going to comment, especially when I saw this thread had reached 3 pages, but heck, coffee is one of my biggest pleasures on tour. So I'll wade in.

I use a Melitta single cup funnel and #2 filters. I like being able to buy stuff at grocery stores along the way. Sometimes they don't have # 2 filters, so when I start to get low I start looking. I've had to use #4's before when I was out and couldn't find #2's. They worked, but were a hassle, and as soon as I found some #2's I chucked the #4's. Finding good coffee can also be difficult. Bigger stores usually have a selection of grind-your-own and it's fun to sample them. I've resorted to Folgers at convenience stores in a pinch. I have to have coffee, right? One of the nicest surprises was finding some really good locally-ground coffee at a little ma-and-pa grocery in Clark Fork, Idaho. I thought I was going to have to drink Folgers for sure, when there it was!

I heat water in my regular MSR pots (the old stainless steel standbys.) I spill a little water when I pour, but I don't want the extra weight of a kettle with a pour spout. It would be nice, but I'm doing fine.

I bring a plastic, insulated travel mug with a lid. It keeps the coffee hot longer (I like HOT coffee) and it doesn't weigh as much as my favorite steel Starbuck's insulated travel mug with lid.

I pack the funnel inside my pots, along with a baggie full of filters, a sponge, the pot lifter, and my Campsuds.

I use a stove which burns unleaded gas, and always make sure I have plenty of fuel so I can drink as many cups of coffee as I feel like (and also have enough fuel for food.)

It's my system and it works for me.