Looking for a good macro Lens? - 1

I have a Nikon D5000 camera and I'm looking for a good macro lens. I know that the Nikon 60mm macro lens in a pretty popular lens, but it's a little bit pricey if you're on a budget. I've been looking at alternate brands like Tamron and they seem to have some really nice lenses.

In particular I looked at:
Tamron SP AF60mm f/2 DI II LD (IF) 1:1 Macro Lens
Tamron 90mm f/2.8 SP AF Di Macro Lens

They both got many good reviews, but I was wondering which would be a better buy. I mostly shoot snowflakes, flowers, small objects, and insects. I want to be able to get a very close up shot without being so close to the subject that the lens interferes with the lighting. I'm also looking for a lens with a deeper DoF and nice natural background blur and bokeh. Which Tamron lens would be the better choice? Other lens suggestions are also welcome, I'm looking for something within the $250- $450 range.

I'm generally not a fan of Tamron lenses, I prefer Sigma. I use a Sigma 50mm f2.8 macro which has a close focusing distance and a relatively short lens barrel, so it shouldn't interfere with on camera lighting. Preferably, you should use a ring flash for macro work or off camera lighting, in which case barrel length becomes irrelevant.
If you want a longer working distance, the Sigma 105mm f2.8 macro is also tack sharp.

You said that you want a deeper dof, then said you want a nice b/g blur - the two are opposites. Also, as dof is dependent on camera to subject distance, as well as aperture, the close distances involved in macro work inevitably lead to a shallow dof anyway - you'll finding yourself stopping down to get the necessary depth of field when you are very close. Even then you may have to shoot at different focal points & stack the images in software.

The Sigma's are also good portrait lenses too. Here's a macro shot with it;

and a portrait;

Costs around £250 so within your budget range.

The new Micro Nikkor 40mm AF-S DX is reputed to be a very sharp lens, and inexpensive as macros go. The catch is that the working distance is short, and it would have more perspective distortion than desirable for close portraits.