One thing to consider that is often overlooked (or at least not explicitly mentioned) in the discussion of the HDR workflow is whether or not you intend to actually need or want to work in full 32bit for post-production prior to rendering an LDR image.
Oloneo and SNS do not output 32bit files (hopefully I am recalling this correctly - it's been a while since I trialed these applications), so your "HDR" workflow ends in those applications. In contrast, Photomatix, Expose and PS merge and output 32bit files (in various HDR formats - Expose has always provided their own format (.BEF) in addition to TIFF, HDR and EXR). Photomatix's batch merge utility is hands down the most flexible and robust. I have used all of these applications and find that certain ones are more appropriate for a particular task than others. I use Macs, but ran Oloneo and SNS in WindowsXP (via Parallels) and they worked fine, if you care to go that route. I find that the Nik tonemapping is way too aggressive and halo prone, and the color shifts are difficult to control - their merge utility is weak. photoshop's merge to hdr pro, as well as photomatix and expose's merge utilities all have their strengths and weaknesses in their control of ghosting and alignment - try the free trials to see which suits your approach best.
I would suggest Photomatix or Expose3 (in addition to of PS), with the idea that, as with most HDR workflows, you are not trying to produce a "final" image from these applications, but you are trying to get a good tonal range compression with control over white balance, local contrast and saturation with the intention of exporting a 16bit TIFF for further processing in Photoshop, etc. Recall also that Expose has a Photoshop plug-in version called Float32, if that is more convenient access to their tonemapping than working outside of Photoshop to perform your tone mapping.
FDR Tools is another application that has very powerful HDR tools, but is a bit quirky to use.
It all depends on what you plan to do with the data once you have acquired it.
Also - Photomatix is in the process of beta release for version 5 - you can download it and test it yourself!http://www.hdrsoft.com/download/betas/pmp50.php
Here is a list of HDR applications (somewhat current):http://www.hdrlabs.com/tools/links.html