In all honesty, it'd be much better, both for performance and for price, to build your own custom system.
It'll seem a bit intimidating at first (trust me I've been there), but once you've done your homework and you have a pretty good grasp on the concept you'll wonder why you ever considered a thermaltake or whatever else.
Basically, you'll need:
Most of your parts you'll probably be getting from dangerden
so check them out first and do a bit reading.
Depending on what you wanna cool, you'll need to appropriate waterblocks. The CPU block you'll want the TDX block, and if you wanna cool your GPU as well (I recommend it, results are amazing), you'll wanna look into a MAZE4 block.
Pump is pretty important as it keeps water moving. There's a lot of debate over the AquaXtreme 50z and the Swiftech MCP650, both are pretty much the same and it doesn't particularily matter, comes down to personal preference basically.
You'll want 1/2" Tubing and fittings for higher waterflow.
Reservoir isn't neccasary, but it makes it easier for you to fill/bleed the system so I'd recommend it, as well as it means you don't have the same liquid running through as often. I feel that acrylic reservoirs are a bit risky as they can crack and leak pretty easily, this
will not leak and I'd say go with it. If space is an issue, you can use a T-Line with a DD fillport, but they are harder to fill/bleed than a reservoir.
Radiator is another important part, rather than buying a radiator from DD or anywhere else, Weapon
of XS mods a car radiator to handle 2*120mm and seems to be favoured there. Contact him for details, they run around $80-90. You'll also wanna pair it with 38mm thick fans for increased airflow.
Coolant, you'll want a mixture of 90% distilled water and 10% zerex. This stuff won't conduct electricity, won't rust, and will keep junk from building up in your system. There have been people who have had this coolant leak, cleaned up their systems, and still had them run.
And I think that's about all, anything missed in here go ahead and shoot.