There are minor electrical, body, badging, and shock differences.
The LX has side and rear plastic body cladding.
The LX has body colored mud flaps.
The LX has different shaped headlights and front grille.
The LX has clear side marker lenses.
The LX came with a different sound system that has the sub in the console and a 6 disc CD.
The LX does not have a rear sub-woofer so the right cargo area panel is different.
The LX does not have speakers above the 3rd row seats.
The LX has various Lexus badges (front, rear, engine, steering wheel, and others).
The LX has different alloy wheels and center caps.
The LX has softer shocks.
The LX was equipped with the Auto climate control that was avail in '97 40th and CE models.
The LX, reportedly, has a higher quality leather.
The LX uses different FSM and EWD manuals and may have different colored wires so it's a good idea to use the appropriate manuals if you are a DIY guy.
Some of the LX interior brackets are painted different colors than the corresponding bracket on the LC.
The LX windshield tint is bronze and the LC tint is blue. (Per NorCalDug 14.May.2004)
The LX has built-in cell phone (Optional & '96 technology)
The LX Left Rear sliding window is fixed and does not slide open. (All LX's with or without optional cell phone)
(This slider had cell phone antenna on it)
Lexus dealers will provide the vehicle service record for all work done at any Lexus dealer.
The diff locks were optional on both the LX and LC. Approx 7% of LC's had the option. Nobody has supplied a knowledgeable estimate of the number of LX's with the option.
OME and other vendor's suspensions will work on the LX. There are no suspension and chassis differences other than the aforementioned softer stock shocks on the LX.
The above list is probably not complete. Those with LX's can fill in the differences.
(Corrections per Alaska's comments below...)
(Additions per medtro's comments below...)
Additions 9-Sept-2004
The LX has a different style key providing a little more security
The LX has a smaller center console due to the CD changer & subwoofer
The LX has a higher quality (but still 'fake') wood trim compared to the Toyota option
The LX rear bumper is slightly different
The LX flares are integrated with the plastic side cladding. This is different than the LC.
The LX came with a small FAK (First Aid Kit)
Additions 29-Jan-2005
All LX's have oak (aka tan) leather guts. Grey was not available.
The LX has more sound deadener.
The aluminum step on the LC is covered with plastic on the LX. I have verified that some LX's have the aluminum step under the plastic and some do not. Raven's did not have it but Troutrunner's had the aluminum step.
Addition 25-Sept-2005
All LX's have the rear diff-lock wiring harness from the cowl to the rear quarter. This harness is present even on those vehicles without the diff lock option. On the LC, only those vehicles with the diff lock option have the proper wiring harness.
Addition 28-Feb-2006
The 1997 LX got color matched paint on the running boards and roof rack. These items are painted black on the LC.