Sharpening in LR3 is much improved (at least in theory) because it includes masking. However, the problem is that it only operates for the whole of the image. If you have a studio portrait or a detailed landscape that may be fine, maybe, but even then you may want to do regional sharpening (or blurring). If you have a "mixed" subject (say musicians and a drum kit) where you may want to sharpen some parts of the image and blur others it may not work so well, even though the masks mean the sharpening is restricted to the contrast boundaries.
Noise reduction in LR3 doesn't include the masking and I think is probably unchanged from LR2 though it will probably receive an update for final release. Once again, it will affect the image as a whole which is generally not what you want.
I suppose one approach would be to have two virtual copies of a Lightroom image (1) denoised and then (2) sharpened for different parts of the image and combine them in Photoshop (in each case). Perhaps that might be worth trying if you don't have noise reduction/ sharpening utilites though it could take a while.
I use Neat Image for noise reduction on the minority of my images (even at high ISOs) that may need noise reduction. I then focus that by combining with the non-NR image using layers and masks, either surface masks or custom ad hoc masks.
When I was performing noise reduction on high ISO digican images I also used the Photoshop technique where you blur the colour layers and sharpen the luminosity layer in L*A*B
mode.
Noise reduction happens before sharpening. I use PK Sharpener and still do round trips from Lightroom for sharpening. It provides sharpening layers so you can adjust parts of the image with masks or control highlights with the opacity sliders or blend-if sliders.
You can no doubt do the same sort of thing for sharpening manually and record actions to partially automate it in which case I would personally favour high pass filter but a utility such as PK Sharpener is useful because it make the whole process simpler and quicker while retaining full control. You can also get a free sharpening utility from The Light's Right.