Here are some tips I got from a good mate in the US and where to eat and what to see. Lotus of Siam I've tried - it's great, it has a cheap buffet lunch (would only go for lunch, not dinner) - great value, a little off the strip so you need wheels to get there, but at $5.99 for all you can eat, you can't beat it! There is a great wig store next door too..... if you like wigs (my mom does!!):

Here are a couple suggestions...
One of the best thai places supposedly in the country - I think it's pretty good and it's super cheap.
Lotus of Siam
Cuisine Thai
Hours Daily 11:30am-2:30pm and 5:30-9:30pm
Address 953 E. Sahara Ave. #A-5
Location East of the Strip
Reservations Reservations strongly suggested for dinner
Phone 702/735-3033
Prices Lunch buffet $5.99; other dishes $3.95-$14
Credit Cards AE, MC,

One of the celebrity chef places in Vegas that is fairly reasonable and interesting french bistro food.

Bouchon
Cuisine Bistro
Hours Daily 5-10:30pm
Address 3355 Las Vegas Blvd. S
Location Mid-Strip
Reservations Reservations strongly recommended
Phone 702/414-6200
Prices Main courses $17-$30
Credit Cards AE, DC, DISC, MC, V

Good old fashioned America food from our southern area.
Rosemary's Restaurant
Cuisine Nouvelle American
Hours Mon-Fri 11:30am-2:30pm and 5:30-10:30pm
Address 8125 W. Sahara
Location West Las Vegas
Reservations Reservations strongly suggested
Phone 702/869-2251
Prices Lunch $12-$16; dinner $18-$29
Credit Cards AE, MC, V

Best Mexican food on the strip
Border Grill
Cuisine Mexican
Hours Sun-Thurs 11:30am-10:30pm; Fri-Sat 11:30am-11pm
Address 3950 Las Vegas Blvd. S
Location In Mandalay Bay, South Strip
Reservations Reservations recommended
Phone 702/632-7403
Prices Main courses $15-$20
Credit Cards AE, DC, DISC, MC, V

Very good New Orleans type cusine - they have one of the best places in NO and they opened a place in Vegas.  This is the most expensive option.
 


Commander's Palace
Cuisine Creole
Hours Mon-Fri 9-11am for breakfast, daily brunch 11:30am-2pm, dinner 5-10pm
Address 3663 Las Vegas Blvd. S
Location In the Desert Passage in the Aladdin Hotel, South Strip
Reservations Reservations suggested
Phone 702/892-8272
Web site www.commanderspalace.com
Prices Lunch $16-$28; dinner $25-$39
Credit Cards AE, DISC, MC, V

Hope that helps!  I still like the Begallio buffet - I do that every time - I think it's the best buffet in vegas.

If you want to see a very popular and cool show - probably one of the Cirque De Soeil shows.  I saw their O show at the Begallio.  To get tickets start lining up by their ticket office around 3:00 p.m. the day of the show you are interested in getting in and you can almost certainly get tickets since people cancel etc.  Tickets are pricy - I think they were like $100 a person - but the show has dramatic effects and all the seats are good. Considered one of the best shows in Vegas on the strip.