not the magnetic lasso - if you want good crop lines, you need to do it by hand.
get the polygonal lasso, and make small selections very slowly.
if you accidentially double click and select it, hold SHIFT (notice the little + on the tool) and start making your selection. once you click for the first time (with this particular tool) you can release shift, and continue with your selection mayhem.
ALT, conversly, does the opposite and will subtract from the existing selection (again, see the - sign?)
all the selection tools work this way. with the MARQUEE tools (square, circle, bla bla bla) you can hold ALT, and click, and the tool will select via the CENTER of the tool, and expand out, if you hold shift whie using these tools, it makes them constrain to a perfect square\circle. combos of ALT+SHIFT are quite handy sometimes.
most every tool can be used in conjunction with ALT\SHIFT. play around, see what they all do. its quite fun //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
but i do all my selections (cutting people, cars ect) out by hand. unless its some smooth\curvy shape, i dont use the pen tool. but i do all my comics\cartoons\drawings with vector based photoshop tools (ie, pen+shape)
i love photoshop.
and remember kids - USE LAYERS!
//edit
MAGIC WAND IS ONLY GOOD FOR REALLY HIGH RESOLUTION PICTURES, HACK AND SLASH, OR NON-ANTIALIASED IMAGES!!!
or you really know what you are doing. trust me, the magnetic lasso and the wand are some of the biggest wastes of time in photoshop.