I like pens with a smoother glide. I can feel the catches on the paper when I'm writing, and it's distracting.
For something cheap, I really like PaperMate. I can usually pick up the 12 pack of Blues (according to their website, they're called WriteBros) for under $2 CAD. These are actually my favourite pens. Sometimes I just watch myself write, and it almost feels like there's no pen in the middle, just my hand doing the drawing.
The Flexgrip Ultra are softer in the hand, but I find that the tip of the pen isn't quite as secure in the case; it's not going to go anywhere, but when you move the tip on and off the paper, it'll sometimes make a clicking noise as it hits the side. Still a nice smooth glide.
The erasable pens aren't really worth it imo; they're not very smooth to write with, and they don't really erase very well (of course, it's probably been 10 years since I've tried one; maybe they've come up with better erasing technology by now ). They also smudge a little more.
The Eagle doesn't feel as smooth as the WriteBros, and I'm not partial to the feeling of the case in my hand, but that's just a personal opinion. I think they may be cheaper than the WriteBros though.
The Gels of course are going to be the smoothest, but they dry much slower, and as you said you tend to smudge, I would advise against them.
http://www.papermate.com/pages/products (No, I don't work for them )