There aren't a lot of terrible skis out there from all the big ski names).
You can read a lot of the threads here to get some idea of some popular skis (just browse all the threads asking about purchasing advice) or from the gear reviews section including "expert" reviews such as this one:
But when it comes down to it, you have to identify a decent demo shop and ask questions to the staff and go with their recommendation based on telling them what is your skill level and what you want to accomplish, and how you want to ski.
If you don't want to go wrong,
-be sure you are willing to spend the extra $ for a true demo rental; and not just skis designed for rental market. The $15 shaped ski package probably isn't going to get you a good equipment (but fine for the true beginner).
-be sure they are at most a couple seasons old so have the latest and greatest in technology.
-For frontside groomer ski, the feature to look for are it should be around 80 in width.
-have some blurb or spiel about "early rise" or "rocker" technology.
-look like they are in good condition with sharp edges and waxed bottoms.
-Shiny graphics: while technically has no impact lets you know the ski is relatively new and in good condition..
If you already have a shop in mind and they have a list of their skis they carry, post it, and I'm sure people can pick out what to try from it for you.
If the resort has a true demo program where you can try as many skis as you want for the day(minus your time to do the swap) maybe it is worth it to try that out and find what you like.
All that being said, if you don't have boots, that is also a key thing that will greatly affect your day. If you're renting boots, be sure to take your time fitting those rental boots.