Recommend buying low end right now and getting much better later?

Well, I'm stuck with an x800 that I've had for 2 years, so I think it's time to upgrade, especially because the x800 lacks 3.0 and 4.0 shader model support. So, what I've been thinking of doing was buying a low end directx10 card right now (around or less than 150 dollars), since I'm really desperate to play some Bioshock. I'm happy with playing games at low resolution and without many high settings, since I've had to live with that all this time. I just want to play new games that are coming out right now. So, without breaking the bank, I would be able to play some directx10 games, and then be able to upgrade later this year or next year to a top end card. The idea of a 9800gts is really enticing, and would fit my plan well. I just want to see other people's opinion this, to see if this is really a good idea.

Forget the concept of "Low End" and "DirectX10" in the same sentence.
The low-end cards do not have the power to make use of DirectX10.

The 8600GT is not a bad card and falls in that category, but there are some better DirectX9 cards that are slightly more and will destroy the 8600GT in performance such as the X1950.

Simply checkout the monthy BestBuy for video cards that is updated each month.

Ok, since most (or all) of the games that are coming out will support directx9 as well as 10, getting a higher end directx9 card will be better than a budget x10?

One generation behind the cutting edge product line is always a nice sweet spot in price versus performance. Thus the sweet spot for economical performance will be the 79xx and X19xx cards