[scarletboa]

i've found that a good 40/60 or 63/37 mix works the best. my personal favorite is the 63/37, but the 40/60 is what is most generally accepted and the most common to find.

anything that's lead free and doesn't have silver in it will be a PITA to solder. that was my mistake when i first started soldering. also, try to get at least a 60w iron or even a 150/230w soldering gun.

my ideal soldering setup:
radioshack 150/230w soldering gun
63/37 rosin core solder
radioshack flux paste, which helps the solder flow better (i only use it occasionally, if needed)
deans ultra plugs (or the hobbyking ones with ridges)
a simple cheap locking plier tool to hold the plug in place
a damp washcloth or sponge to clean the soldering gun tip after each use (very important)
40w solder suctioner if i'm soldering small things such as circuit boards

once i got the proper solder and a proper soldering iron, my solder joints improved DRASTICALLY. i went from having giant solder globs that would only stay put 50% of the time and would often not last during use due to them breaking loose at high current.
now, my solder joints look professional and are as good, if not, better than pre-soldered packs that you can buy from the hobby store.