I recommend a blend of juices that includes blueberries, strawberries and watermelon. These fruits are a good source for natural energy. You should also get used to drinking a smoothie in the morning, they can be quite good for you if you use high quality, organic fruits.
I wouldn't stop the coffee all at once. Gradually decrease your coffee intake as you increase your replacement. Feverfew is an herb that has a nice track record when used as a vaso-dilator and may ease your caffeine withdrawl.
As far as a juicer goes...make sure which ever one you choose can handle pulp, peels and cores. I have heard good things about the Jack LaLane juicer. It is modestly priced at around $100, has lifetime warranty and is endorsed by Good Housekeeping. You could spend a lot more money and buy an Acme ($175) or a Champion ($250+) but I suggest you buy the LaLane and spend the difference on high quality fruit. Please note...I have never used a Lalane juicer. I personaly own a Black and Decker.