Since you've stated that you are at an intermediate level of riding, I would imagine that you have a style of riding that you prefer. Once you have decided what kind of riding you're going to do, remember that it's not just important to decide on what type of board you'll be riding, but the combination of boots and bindings as well.
Note: Different riders have different preferences and combinations and there are always exceptions to the rule, so bear this in mind when selecting a board.
Shapes
Before I list the different types of riding available, you should be aware of the different shapes that snowboards come in. The shape of the board will have pros and cons to it, so be sure to lay the board down and get a good look at its shape before deciding. Here are the three most common types of shapes (note: there are variations or these boards, so bear that in mind).
Camber
This is when the center of the board is at an upward curve, leaving the ends of the board to touch the ground. The center of the board will only touch the ground when a rider is on top.
Pros
- Excellent stability
- Increased edgehold
- Great for carving
- Greater "pop" (spring from jumping)
Cons
- Requires more effort to turn
- Easier to catch an edge
Rocker
Also known as reverse-camber, this board is the opposite of a camber, with the center of the board touching the ground and the ends up the board pointed upward and away from the ground.
Pros
- Easier to turn
- Easier to flex
- Floats well in powder
- Less likely to catch an edge
Cons
- Less stability (can "wash out" easier)
- Less "pop" (spring from jumping)
Flat
As the name implies, this board is completely flat from the center to the ends (with only the tip and tail curved).
Pros
- Decent edgehold
- Decent maneuverability
- Good transitioning
- Excellent for rails
Cons
- The increased versatility sacrifices some stability and maneuverability
- Some riders complain of a "dead" and/or "damp" feeling
Types of Riding
Now that you have an idea of the different shapes that snowboards can come in, here are the different types of riding available and the appropriate board and gear.
All-Mountain
This is probably the most common type of riding because most riders like to try a bit of everything. It is great for riding in both backcountry and groomed runs. This type of riding is less specialized than the others, which also makes it a great type of riding for beginners. Once you are past the beginner stage, you can specialize your riding or stay with all-mountain.
For this type of riding, your best bet is to purchase a stiffer (but not too stiff) board. Stand the board up vertically and push downwards from the top to determine the board's stiffness/flexibility. Different boots have different stiffness level. You can turn faster with softer boots, but you will have to use more strength from your legs and feet to stay stable. Most will advocate that beginners start off with a stiffer boot, but suggest that advanced riders take on a softer and more flexible boot.
Freestyle
If you're interested in performing tricks on the slopes and in the terrain park, then you will definitely want to purchase a shorter and more flexible board with twin tips. This will make it easier to absorb impacts from riding boxes, rails, etc. For increased control, I would recommend a lighter boot with a stiffer forward flex.
Note: This is for the terrain park. If you want to ride on the half-pipe, make sure that you invest in a stiffer board. On the contrary, stiffer boards will not absorb impact in the terrain park.
Freeride
If you like riding on steep slopes, deep snow, and backcountry, make sure that you purchase a stiffer board, so that you can pull off decent carving with excellent stability. I would suggest a stiffer boot that is soft on the upper part to make your transitions easier on your shins.
Racing
If you're interested in racing, there are specific narrower boards for racers with an emphasis on carving and speed. There are also plate bindings and hard plastic shells boots that differ from the typical gear you usually see in shops.
Conclusion
To end off, if you want to find the best deals, visit the shops during the spring and summer months and see what gear they have available. Like one user has already said, be sure to ask for stock from last year. I paid sixty dollars for a pair of boots that were two years old (but had never been used). You'd be surprised at the deals you can find.