There are so many that it would be difficult to choose.
Janeway's almost every line is worth gold ...

This does not mean the other characters didn't get beautiful lines but Janeway's were almost always awesome.
But I guess the purpose of this thread is to collect them ... so I'll give you examples with every character (and thanks to Chrissie's Transcripts site at
http://www.chakoteya.net/index.html):
Janeway (Renaissance Man)
EMH: I'm not going to decompile?
JANEWAY: You'll probably outlive us all.
Chakotay (Resolutions)
JANEWAY: Is that really an ancient legend?
CHAKOTAY: No. But that made it easier to say.
Tom (Prey)
ALPHA-HIROGEN: I once tracked a silicon-based lifeform through the neutronium mantle of a collapsed star.
PARIS: I once tracked a mouse through Jefferies tube thirty two.
Tuvok (Learning Curve)
NEELIX: I feel that my services as Morale Officer are required.
TUVOK: I assure you, you are wrong.
Harry (Live Fast and Prosper)
TUVOK: The next time I visit the holodeck, I expect to find my programme restored to its original parameters.
PARIS: I'm telling you, Tuvok, we didn't do it.
KIM: I wonder how the Oracle would look in a sombrero.
B'Elanna (Extreme Risk)
TORRES: When I was six, my father walked out on me. When I was nineteen, I got kicked out of Starfleet. A few years later, I got separated from the Maquis. And just when I start to feel safe you tell me that all of our old friends have been slaughtered. The way I figure it, I've lost every family I've ever had.
Doctor (Drone)
EMH [on monitor]: Rise and shine, Lieutenant. It's oh six hundred hours. Early bird gets the gagh!
Neelix (Fair Trade)
NEELIX: Voyager is a wonderful place to be. People here are very fortunate.
VORIK: I would concur.
Seven (Demon)
SEVEN: Each square kilometre of this planetoid is less appealing than the last.
Kes (The Cloud)
KES: If I were Captain, I'd open every crack in the universe and peek inside, just like Captain Janeway does.