I'll be visiting Las Vegas for the first time in October and would like feedback regarding the Luxor and Tropicana. Also, what are the must sees (have heard the Sigfried & Roy show is not worth the $$$). Thanks.

You need to do a little reading via the above "search" function, Annette...then come back with questions specific to your tastes/goals for your trip. This question is reviewed several times every quarter. The issue of 'best shows' is a common one, and there have been a few posts about this in the past 3-4 days (check out "O" and Mystere).
As for Luxor vs. Trop: take the Luxor, no question. The rooms inside the pyramid are more trouble to get back and forth to, but the view is certainly more interesting versus the recently added rooms in a couple parking lot additions.

No contest! Lulxor hands down. The Tropicana is ugly, run-down & noisy & difficult to navigate. Luxor is strikedly original in archetectue, open & airy. We just returned from a 4 day stay there and would return. The disadvantage of both hotels is that they are a long walk to the center of the strip.

We just got back from Vegas 2 weeks ago and stayed at Bally's. I would definitely recommend it unless you have children, as it is not family friendly.
I have stayed at both Luxor and Tropicana on past trips, and would recommend Luxor if you can get a tower room. I was not at all happy with Tropicana; the hotel is getting old and it shows.
A definite must see is Forever Plaid at the Flamingo Hilton. Seigfried and Roy are definitely worth the money.
Enjoy your trip.