Well I don't like the 30" monitors because they don't do 1080i natively, they have limited scaling options, and sometimes limited OSD options. If those don't matter to you, the 305T is probably a better deal than the 275T. I myself may be holding out for the 275T but the 305T is just too far out of my budget and it has limitations that I don't like (such as limited inputs). If you have dual 8800GTXs that may already solve the problem of gaming on a monitor like this.
The 3007WFP is a better choice than the 305T, and it costs roughly the same or perhaps cheaper. It has less input lag, according to
DigitalVersus, and it features a very wide-viewing-angle S-IPS panel. The 305T probably has a better black level because of its panel technology. In the end it's a toss up but I would be edging towards the 3007WFP more. On the other hand I do like Samsung as a brand too so this is a tough choice.
As long as you are talking about 27" screens, don't forget about the 25.5" Planar PX2611W (~$950 USD) that has the same resolution, a lower dot pitch, S-IPS panel, and only 1 frame of input lag. Personally, I think it's a little pricey for what it is but it may just float your boat. I would be going with the 275T over this because it's more feature-packed, it has a record-breaking black level, and the Planar has had uniformity problems.
If you're bent between the Dell 2707WFP and Samsung 275T, I would go with the Samsung just because of brand and perhaps QA. Plus it got a glowing review from ExtremeTech. True the dot pitch can be a downside, but honestly the quality of the screen is what matters most. Since it's a true 8-bit high contrast display you're not going to be seeing big dithering pixels or anything. Sitting back farther is the only solution but it's quite a realistic one. Text will always be easy to see, too.
In fact, X-Bit Labs also loved the 275T:
http://www.xbitlabs.com/articl...-monitors_5.html#sect0
The response time, color setup, and gamut are truly incredible. It is just a bit short of the LED backlight.