A lot of us use a Lamy Safari or Vista (which is clear but the same pen!)--with the charcoal nib rather than the steel one, they're smooth and dependable. (If you want to replace the nib, it's EASY, and you can get replacement nibs from several sources, including JetPens. Here's one of the many tutorials for replacing the nib.)
This one's a favorite of mine, a Waterman Phileas--it's dependable and sturdy, and almost never skips--when it does, it's usually the paper's fault, not the pen's! I've gotten these for a reasonable amount on eBay, and one was a STEAL, complete with a converter. They also come in cobalt blue, red marble, and other colors...
NICE pen. Interestingly, the Lexington Gray ink looks almost black with the Phileas, much grayer with the Lamy--a difference in how they deliver the ink or how the nib is designed, I believe.
Here, I've tested a variety of nibs--click on the image if you want to see them better! I've tested out the Lamy Joy nib, too, which you can also find at JetPens--if you already have a Lamy, this may be the way to go, just replace the nib. New Joy pens can be found for a reasonable amount, though--try Googling!
Interview # 10!-- mentioned on her blog--but they're out of stock till mid-May.)
Finally, you can see a quick sketch done with the Joy nib, Noodler's Lexington Gray ink, and watercolor washes...FUN.
Let us know what YOUR favorite pen is...