Im not sure what prepared food means in NH but in TX it also applies to grocery items like frozen dinners and the pre-made walmart subs. As for hotel tax I think the max is 18% but most of it can be easily avoided if you dont have to stay right downtown.
The only thing that it would apply to in a grocery store is actual prepared food, such as stuff actually cooked/served in the store.
For example, I buy a lobster at Market Basket for $4.99/lb. I get a nice one at 3 lbs (the ones you normally see in TX are about 1 1/2 lbs if you're lucky.) So rather than steam it myself, I pay the room and meals tax of $1.35 for them to steam it for me. Now personally, unless I'm looking to cook them on the stove/grill, I'd rather fork over the small amount to have them do it.
Dinner in a restaurant is also taxed at 9 percent. While higher than MA (6.25%, IIRC) or Maine (5%), I don't pay sales tax on ANYTHING else I buy--food, clothing, appliances, a new vehicle, nothing. There is of course tax on alcohol, tobacco, and fuel, but they're far lower than neighboring states. I figured I saved myself $3000 when I bought my last vehicle being a NH versus a Maine resident, because not only would I have gotten nailed with ME sales tax, they would have hit me up for an additional 5 percent of sales value when I went to register the vehicle in ME (and believe me, the cops there are friggin Nazis when it comes to checking plates parked at a residence more than a few days.) Income taxes in Maine are absolutely ridiculous, with marginal rate of 8.5 percent of singles making more than $19,950 or married/joint making more than $39,900/year.) MA is only slightly better with a 5.3 percent flat tax based on federal AGI.
But as far as hotels go, even in the 'burbs you're going to pay more than 9 percent a night in Texas, considering the state gets 6 percent, the county (depending gets 2-3 percent, the town gets another 3-4 percent, and like you said, "special" taxes like Houston's sports facility taxes can easily push it to 20 percent.)
