Should I liquid cool or air cool?

if your not oc-ing then liquid cooling is useless to you, air will be more then enough.

Since you arent a overclocker and have your mind set on a thermaltake water system then I would have to say no. Air will have to do you and with good airflow you can have very silent fans on CPU and GPU so youll have silent too.

The only reason you should even consider taking the risk of liquid cooling is if you plan on overclocking your system. Since you don't seem to be planning on this, I will second the suggestions to stick with air cooling.

As far as to whether or not a liquid cooled system requires a lot of maintenance, it all depends on how careful you are when you first design and build your cooling loops. I'm an old hand at this kind of maintenance, though, since I used to work on photo developing equipment in college. If you are cautious and take time to clean the parts before you assemble them together, then you can easily go a year or more without having to do anything other than add more fluid into your loop (you lose a certain amount of fluid over time just through osmotic release from PVC tubing). I used pure distilled water in one of my first LC builds, and was changing the fluid every three months because of algae, and that got old quick because I had to wash the system with vinegar every time I flushed the loop. That's changed, though, since most of the fluid additives you can buy now have antibiotic agents that will retard algae growth without smelling like antifreeze.

As far as having any parts go out, the only moving part in the cooling loop should be the pump. It's bad news if your pump should fail, so it is a good idea to monitor flow activity just to be sure. It only takes a few seconds for your processor to hit temps that can start a boil-off in your cooling loop if the fluid isn't moving (especially if you are using additives that lower the boiling point of the fluid). Most good pumps have a 3 pin fan plug that you can connect to your mainboard and monitor RPMs (at least, Swiftech pumps do this). If nothing else, you can use a flow indicator to be aware of any issues. But then, these pumps are more reliable than most fans, since you don't have to deal with dust as a factor (just stay away from the cheap aquarium pumps).

If you do decide to try out liquid cooling, stay away from TT if you want to get the best bang for your buck. If you have a bit of money to spare, put a loop together using parts from Danger Den and Swiftech. While TT liquid cooling is marginally better than the best air cooling, building your own custom loop will yields temps as much as 10°C better than what you can get from TT.

I have been doing much the same as you, eyeing up various cooling solutions without any firm plan to overclock. Hell, I need to do some serious research there first, turns out teh intarwebz isn't that helpful after all, who'd have thought it?  

Don't bother with liquid cooling. As has been said, air is better for your circumstances. It's safer, less tempremental, lower maintenance, and what's more you can get some truly wicked looking towers these days that make your computer look like some weird 50's space rocket. That's just too damn cool to pass up, aint it?  

even with a high end cpu air will do just fine. just make sure you get an aftermarket one of good quality (name brand).

Air cool it!!!!