Your manufacturer's warranty expires in a year. If anything goes wrong that is a design or manufacturing fault, you are covered.
If you are a student, get the discounted AppleCare! That will give you an extended 3 years warranty (and phone support).
Over the 3 years, anything can go and you are not covered. Some computers will fail and some will be running in 6-7 years with no major problem. I have two eMacs (2003) that I recently took back from my garage and started using again. One of them is running Leopard, the other one is running Tiger (the best OS ever). I can hear some processor noise (or whatever that is) and the fans are loud. But they work and in basic tasks, they are surprisingly snappy. Meanwhile, I had terrible issues with a few C2D MBPs and MBAs.
Yours will be hopefully a computer that Apple will support for a long time. I remember that even in mid-2006, you could buy PPCs that could not run Snow Leopard. Those computers officially became a dinosaur in three years. I'm sure that they will run for many years to come, but in the meantime it's always nice to be able to do an OS upgrade in a few years.
Yours will do that I think, unless at one point the i3 dual cores will prove to be unsupported whereas the quad-core machines will be able to run a future OS. But that is just pure speculation and currently, you are better off to save your money, enjoy the entry-level that later you can upgrade and in three or four years sell and buy a new one. In three years, your mac should still worth around 35-50% of its original price.