Bad pens infuriate me. Scratchy pens that leave a faint trail of ink in uneven thickness all over my paper infuriate me.
Let's just say I'm always on the lookout for a good pen. Once you use a pen that leaves a thick, even coat of ink, you'll never go back to generics. Trust me.
THE BEST BLACK PEN: Pilot V5 RT (the RT stands for retractible)
The retractible versions are getting increasingly hard to find at stores. Pilot V5s have caps (non-retractible) and are easier to find, but I've had a few of them leak all over my hands when I open the cap, so I stick to the retractible version.
THE BEST COLOR PENS: Paper Mate Flair
I'm a high school teacher, so I use a lot of colored pens for grading. I'm also a grad student, so I use colored pens for outlining articles. These pens are amazing for color coding notes, organizing information when you outline, and--most importantly--doodling. They write like thin markers, so you can't always use both sides of the paper, and they run out of ink more quickly than Pilot pens, but they're so good that I don't even flinch before buying a new set. I usually get the 5-pack, but a lot of my teacher-friends opt for the 12 or 24 packs because of the larger variety of colors.
(Photos at Giant Coffee in Phoenix)