I would stay away from the built in units. They are pricey and should you need to replace the unit, you'd have to conform to the footprint of the old one.

Superautomatics have about a 15" square footprint and can live happily on a countertop. If you want to plumb one in, that wouldn't be a difficult operation as long as you got a plumbable model. There are several excellent models made by Gaggia, Jura and other mfrs that are perfect on the countertop. Give a look at coffeegeek.com and wholelattelove.com for lots more info!

We used to have an expobar + grinder which my husband loved and which I liked for steaming milk and getting hot water (I'm not much of a coffee drinker). But in the course of planning our kitchen renovation, we decided we didn't want coffee-grinds all over the kitchen. We considered a built-in, and decided on a countertop superautomatic instead. We bought a high-end capressa jura, after reading positive reviews. But we just weren't happy with it - it's true that we didn't have coffee grounds all over the kitchen, but it took forever to steam a cup of milk or draw out hot water. So we sent it back and got a refund, and bought a pod-specific pasquini livia, which we're now both extremely happy with. Espresso-snobs look down on pods, because the coffee isn't freshly ground, but my husband loves how much less cleanup he has to do, and I love that there isn't mess all over the place (despite his attempts at cleanup), and the thing has enough steam to power a locomotive - I can steam a cup of milk super-fast (or get hot water fast). We're finally both happy with what we have. We chose the countertop super-auto over a builtin because it was smaller, but we ended up really glad that it had the other advantage of being replaceable when we hated it. If we had enough space for a separate coffee bar with its own sink, we might have stuck with the expobar + grinder setup, but we decided we'd rather use the space for a desk, and overall this seems like a really good space-and-mess-saving compromise for us both. The coffee tastes good to us, too.

Here is a link that might be useful: pod-specific livia

Built-ins: The Gaggenau, Thermador and Miele ones all fit in the same size cutout. Mine's a Miele and the way it's set up, I could just yank it out of my cab, the shelves are finished on all sides and use it as an open shelf shoudl I not find anything to fit. That said, had I to do it again, I wouldn't get a built-in. My old freestanding Saeco made coffee that was as good and it cost me almost $1200 less than the Miele. The Miele does look cooler though.

I used to dream about having a fully plumbed-in, pro-level espresso machine, but finally gave up on the idea because I simply couldn't justify dedicating so much of my limited counter space to it. So, I got a La Pavoni Europicola, which is only 7.5 inches wide and slides away under the cabinets when not in use. If you are already using a semi automatic, the learning curve to master a lever machine will be minimal. If you have a lot of espresso drinkers in your home, or frequently entertain large crowds of espresso drinkers, a semi-automatic machine may make sense. But for low volume use, I think a lever machine gives you everything you need for great coffee, and takes up a lot less room.

I just purchased a Keurig B70 model pod coffee maker and love it! It is very nice looking. It does take up a bit more room then my whole pot coffee maker. But I like the fact that it brews one cup at a time. They recommend that you keep the coffee pot on all the time, but since I use it mainly in the am I find it only takes a few minutes to heat up for brewing. If you decide to leave it on, it stays lit up really well.

This version allows for a variety of coffee sized cups including my large coffee mug for my car. I will admit that the true coffee connisseurs will turn up their nose at the pod machine, but I find the coffee just fine as compared to going to our local corner store for a cup of fresh brewed coffee.

Here is a link that might be useful: Coffee Pod Machine