I'm quite optimistic about the future, but I seem to be posting anti-predictions instead of predictions. Perhaps I'll post positive predictions someday, but today I have some more negative ones:
Quantum Computers. Yes, I know that there's a now quantum computer chip but I'm pretty pessimistic anyway. Quantum computers let you explore 2N states with N quantum bits; it would take 2N regular bits to do the same. However, I think the difficulty of maintaining the entangled quantum state will be proportional to 2N — that is, adding one quantum bit entangled with all the existing ones will double the difficulty of preventing decoherence. To explore a large search space, it will be far easier to build more very simple conventional processor than to build one very complex quantum processor.
DNA Computers. Making DNA compute for us seems like a cool idea. We can grow this stuff in vats and have hugely parallel computers. The problems here are that (a) you have to get the problem transmitted to all the DNA in the vat, (b) there's no guarantee of finding the answer, and (c) DNA just isn't a great medium for the kinds of controlled programs we want to write. Here too I think it will be far easier to build a simple massively parallel computer from electronic parts than to build a DNA computer. DNA does have the advantage of easy replication, but conventional computers will also benefit from self-assembly.
Practical Teleportation. There have been experiments showing that teleportation is possible. The basic approach is to entangle two particles at the quantum level, and then destroy the original, leaving you with the “teleported” one. It's pretty cool. But it suffers the same problem as quantum computers: there's a huge amount of complexity involved in teleporting real objects (unlike movie teleportation, I don't think it matters too much whether they're biological or not), and I'm rather pessimistic about being able to entangle a large number of particles simultaneously.
Faster than Light Travel. Physicists seem to think that faster than light travel is possible using wormholes. The idea is that you bend space and time in such a way that where you are and where you want to be are “close” together in another dimension, and then you leap across. I think this is possible in theory. But bending the universe is going to take far too much energy and cause too much collateral damage for this to work in practice. Instead, we'll have to hope for existing wormholes, and there won't be any that are useful.
So there you go. Another fit of negativity from me. I really should start collecting positive thoughts about the future.