Holiday Valley and SNowshoe are two completely different types of ski resorts. I've been to both, so I'll share some thoughts even though both have been commented on before.
Snowshoe has the best snow in the mid-Atlantic, hands down(190"/year). T-Line and some of the other places do ski truer to 1000' vert, but they don't quite get the snow snowshoe gets. That being said, Snowshoe also gets rutted out fast because it is so crowded. Holiday Valley gets about the same ammount of snow as snowshoe, but is generally has better coverage due to fewer rocks and the type of snow that falls - lake effect.
Holiday Valley is a truely unique ski experience for where it is located. You actually get a sense that you can move around the mountain and ski different styles of runs, an experience that you do not get at most eastern ski areas. They also allow you to ski in the trees, where Snowshoe does not(legally). Snowshoe does have two runs in the Western Territory that are 1500' vert, and are uncrowded compared to the main area. If you manage to avoid getting caught and ahve good snow, there are some good tree rusn between the two. Snowshoe also has a second area called SilverCreek that is by far less crowded, and offers a tubing area. All the lifts there are slow,a nd it has much less vert than the Snowshoe area.
I remember paying something like $29 for an all day lift at Holiday Valley (9am-9pm). Snowshoe will likely be double that this year just for day skiing. Finding cheap lodging is also now an issue, but it can be done. You can stay in Marlinton(sp?), or a the Brazenhead Inn - http://www.brazenheadinn.com/
Apre Ski and Amenities
Snowshoe has a lot more to offer, hands down. Ellicotville is a quaint town, but it simply does not stack up to what Snowshoe has to offer. Snowshoe also has some pretty good resturants.
In all, they are two completely different areas. I am generally the first person to slam Snowshoe, however if you ahve never been there and are willing to pay the extra $$$, it is worth a visit to see if you like it.