sony a100 or nikon d80?

I have been using the Minolta maxxum5 for years and I am looking to purchase a DSLR. I was upset to hear Minolta was dropping out of the digital market so I started researching other options.
I was pretty much sold on the Nikon D80 and went to purchase it and ended up talking to the Ritz sales associate about all my Minolta equipment. He showed me the Sony a100.
I still have my heart set on the Nikon but I do have some nice Minolta lens, including my fave; it's a 24-105mm AF 1:3.5 (22)-4.5 by minolta and lots of filters for it which I don't think I can use on many other lens because the lens is a 62mm.
I knew Minolta had sold to Sony before I did any research but I never explored it because I preferred a company like Minolta or Nikon that had the majority of it's business in the camera biz. I was worried that because Sony has it's hands in so many other areas it might mean their cameras were not as good. It this an unfair assumption?
The majority of my camera use will be for portraits at an in-home studio with light kits etc... so quality is a must esp. if clients want a poster sized enlargement. I read the a few Sony users remark on the noticeable noise on their prints.
I have about 2k right now with the potential for more later.
So if the Nikon is the way you suggest I am fine with slowly getting good glass as I go.
If Nikon is the best choice, can you suggest which lens I should start out with? Don't need the mega zoom right now (100-400). I can get that later. I need a good piece for close-up and portrait. And I will spring for good quality glass.
And if that is your suggestion don't worry about my minolta, I use it every day for personal use, I have a 16 month old son (firstborn) need I say more?

Hi Sammie:

I thought I would take a shot at this, since I use both Minolta and Nikon systems in film and digital. Frankly, I find that Minolta glass stands up to most of the Nikkors, with the exception of a very few of the Nikon lenses. Anyhow, I got a really good buy on a Minolta 5D, and have been very happy with it. This is the platform on which the Sony Alpha 100 is based. The main reason I like this platform is the IS (image stabilization) (pun intended). On the Nikon side, I have a Fuji Finepix S2 Pro, which of course, uses Nikon glass. I have never had a noise problem with the Minolta, but I never shoot above ISO 400, and it sounds as though most if not all, of your shooting will be under controlled conditions, where you should be at ISO 100-200, so I don't think noise will be a factor.
That said, with the amount you have to spend , I would seriously recommend you think about upgrading to a D200, which is a truly serious camera, and at about $250, you can pick up a 55-200 Nikkor VR lens, which would give you the best of both worlds. You can always pick up a used Minolta DSLR later, for a relatively few bucks to shoot the snapshots, and still use your minolta glass.

Yes, definitely go with a D80 or D200. Nikon has never failed me.