Personally, unless the bearings need to be replaced, I wouldn't replace them. While the front wheel is off, stick your finger the in hole where the axle goes and turn the bearings. If they turn smooth, then I'd leave them alone.
If the pads need replacing, then definitely change them. Here are s couple of tips:
1. Once you get the front wheel off (you have to remove one of the calipers to do that, usually the left one as your looking at the bike from the front), remount the caliper and while the old pads are still in there, use a large screwdriver to compress the pistons so once the new pads are in there, there will be enough room for the rotor to fit. That pin that holds the pads in place is in there pretty tight, hence the reason for putting the caliper back on to get that pin loose.
2. DON'T squeeze the brake handle or pedal until the front wheel is back in place. Once it is, give the handle and pedal a couple of good squeezes before you go for a ride. This will prevent a surprise. Don't ask me how I know.

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3. If you want to clean the pistons before you put the new pads in, get a old toothbrush and some brake cleaner to give them a good once over. You'll have to take out the old pads to do that. Once they're clean, put the old pads back in and do step 1.
Fred Harmon has done a good step-by-step which should help:
http://www.pbase.com/fredharmon/brakepads
Change the brake fluid AFTER you get the new pads in place.
Give the fork tubes a good cleaning while you're in there.
If you've never changed your rear drive oil, might as well do it too. Here is a really good step-by-step on how to do that:
http://www.gl1800riders.com/forums/showthread.php?t=271073
Have fun! :thumbup: