This really comes down to what you are seeking. I've stayed at everyone one of these properties, except Tahoe, and have found them to be decent for what they are.

1) If you are looking for a city stay, definitely SF over LA.
2) If you're looking for a beach stay, Laguna will give you a proper southern california experience in the summer, though it can be cold in winter. Also check their conference schedule, as while I've been to this property as a holiday-maker, the bulk of my visits are for investment banking conferences. You will be innundated by the 'sea of blue blazers' if we're there while you're there...including all the pools, etc. Many banks reserve entire restaurants, etc. HMB is much more akin to a scottish climate...it's a unique property (I've gone 2x, as recently as April 2011)...but you don't go there to sit by the beach. Golf is great there. I found service, excluding the concierge, to be very good at HMB both times.
3) If you want to ski, go to Tahoe (in the winter).
4) MdR is the least inspiring of all of these properties. If you were thinking of buying a boat, this would be a good spot to stay, as it sits on an inlet with literally thousands of boats - and boat dealers. Beyond that, unless you had business in MdR (I have some prospective clients just up the road), there's no reason to pick this hotel. MdR is not a bad hotel in any way, just not someplace a holiday-maker should seek out.

The SF property was considered by some to be the top RC in the US. (I've found it quite nice, though haven't stayed since 2007.) I've heard some chatter that the quality of the property has fallen a bit (though this is second hand). (My current pick for top US RC is NYC-CPS - doesn't sound like your coupon is valid there!)

Please let us know what (and when) you pick!