I have been playing with the new Linux beta for the graphics program Xara Xtreme. It is vector program that really is spiffy and the price is right. The Linux version is free although there will eventually also be a paid version which will have non-open source resources, like Pantone colors. The Windows version costs money but, seriously, its only $79 and for the quality of the program that is a total steal.
I usually use Inkscape for my vector work. I'm not a graphic designer and I don't really do much fancy stuff. Generally I use it to create design sketches for clients before I move to actually creating the site and making small, simple graphics. Inkscape is nice little app and it has served me well for years now but it is still young and growing and has much room to grow. Xara Xtreme on the other hand has been around for a long time and they are now taking their refined Windows product and porting it to Linux and Mac as well as making it open source. They make a good product but between Adobe's reign and Microsoft's entrance into the market they did not feel (rightly so) that they would have enough resources to compete. So they decided to follow the Open Source model and move into territory that Adobe and Microsoft are not likely to go any time soon.
I've already been able to do some fun stuff with it just poking around and I'm looking forward to learning more. If I get comfortable with it I may very well pony up the cash to buy the windows version so I can have a solid cross-platform solution. I do own Illustrator 9 but in addition to not being cross-platform I have never felt comfortable with it. Certain things in Illustrator just frustrate and/or confuse me in a way that Photoshop never has. I9 is also getting pretty long in the tooth and I'm too cheap to upgrade a program I don't like, isn't cross-platform, isn't open source and I hardly use, especially for the price Adobe is charging.