Yea I have CNX2. I use LR2 mostly but whenever I need to do some serious exposure adjustment I switch to CNX. My favourite tool used to be the gradient tool but now that LR2 has that, my need for CNX2 has diminished somewhat but it's still a great tool.
Note that LR can already do most of what CNX2 can do and more, just not as good in some areas.
Just placed an order for LR and CS4. There is a promotional deal going on in the US where if you buy both you get a $90.00 discount. Plus, the two softwares were already over $100 (each) cheaper than if I were to buy in my home city of Toronto (Canada).
And as you said LR is more powerful. Especially when used with CS4. Then there is no comparison. Though NX2 does have it's strengths too. But I found in trying to recover highlights from a JPG (yes I know...RAW is much better...was experimenting in JPG) LR did a much better job than Aperture 2.0 (which I also have). Might consider getting the "upgrade version" of NX2 in a few months too.
Though I doubt it. LR/CS4 should be it.
And then there are all the plug-ins for CS4...limitless. It's a software that only gets more flexible in time. You can "custom tailor" it to your needs as your experience and needs changes. Can't do that with any of the other 2 editors. Then there is the fact that you get Adobe Camera Raw.
If you do most of your editing in one I don't think it makes much sense to do other kinds of editing in another editor (e.g. NX2). Could possibly affect the work you did. Just not sure what I'll be using Aperture 2.0 for after I get LR/CS4. LOL!! A glorified browser??