OK keep this in mind. The 9800GTX+ card is the same thing as a GTS250. I have the 9800GTX+ I got for under $100 awhile back and while it's a capable card, I can still max it out fairly easily.
The next best thing in the Nvidia line-up in your price range is the GTX260. Looks like the best of which (based on the reviews) is this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127464It will run you right at $200 (I think there's a $20 mail in rebate though). This MSI brand card also comes with a 1 year warranty. You can find the 260 in other brands with a lifetime warranty for just a little more though.
Now, if you're interested in switching to 'the dark side' ATI cards are a great value right now, and perform just as good, if not better, than their Nvidia counterparts - at a much lower price. Personally, if I were to upgrade, I think I'd be interested in the ATI 5770 cards. These also support HDMI, DVI, DisplayPort.. and the new Eyefinity ATI technology... so they are quite a bit more future-proof than the Nvidia (non-fermi) cards out right now.
Here's a 5770 for under $170 with shipping:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150462But, if it were me I'd spend the $20 more for this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150464Looks like it has faster memory and a bit of factory overclock... probably better cooling too.
And these two examples both come with lifetime warranties...