It is a Zalman 7000AlCu so the fan is part of the HSF unit. And I appreciate the where to buy links, but it appears that nobody has it in stock, I was looking for someone who found a not normally listed store that had some stock left.
I have searched far and wide and not been able to find the Ultra-120 or Scythe Ninja, neither appear to be in stock anywhere.
The ninja seems to be out of stock everywhere at the moment, the reason being is that a new revision of it is being released in just over a week, hence everyone is trying to clear their old stock and make room for the new Scythe Ninja which will be slightly quiter, lighter (and hopefully better performing) than the old one whilst supporting AM2 sockets.
I tend to agree with you, go for the ninja, from the reviews i've read so far, the infinity has little or no performance gain, is a bit louder (apparantly) and weights LOADS - i personally wouldn't want to put in my case due to pure fear of it breaking the motherboard etc.
Personally I think the Infinity and Ninja are going after 2 different areas in the market. The Ninja being for someone going after silence (passive) or extremely quiet (adding a slow speed fan, which there are quite a few good ones). With the spacing of the Ninja's fins, a high speed fan isn't going to show much if any improvement over a slow speed fan. It was designed for passive/low aiflow setups.
The Infinity, with its larger surface area and tighter fin spacing, seems like it will offer better cooling at a lower noise (than retail hsf or other heatsinks) for someone looking to run top of the line gear, possibly OCed as well. Though I've read a couple people getting pretty good results with an Infinity being ducted to the exhaust fan.
I like the Ninja because of it's symmetrical design. No matter what platform, if you use a fan it can be positioned to blow at the back exhaust fan. Also I'm a bit squeamish when it comes to hanging the Infinity+fan off the board. Quite a bit of weight and the mounting for AM2 I hear isn't that great.
Either Thermalright 120 or Scythe Ninja is good. If you want it better then get a high performance fan for it. I suggest the Silverstone FM121 for it. I have the Tt Big Typhoon in mine, before my water cooling and when I replaced the fan with the FM121 I got better results. The fan is quiter and more cfm, thus decreasing the temps effectively.
personally I think you should get a Scythe Mine, it is far overlooked. I read a couple reviews on it, and they showed the Mine either performing at the same level, or a little better then the ninja plus. I personally have it, but I havent tryed it yet. My E6400 comes in the mail tomarow !!! I plan on overclocking to around 3 ghz. its gonna be so insane compared to the 1.5 pentium 4 i have runnin now !