If you can afford it Photoshop is the one to get. Although it's expensive, you could save up for it while using GIMP for now.
http://www.gimp.org/ for linux / windows and many other OS (scroll to bottom of page to find more OS download versions ). its beautiful to use and easy just give it a try - full version/ full support for free since OpenSource or try Gimpshop ( photoshop like version of gimp ) free download at http://www.gimpshop.com/
XARA is your best option among the three, if you have limited budget. You can try the new XARA Xtreme Pro. It has everything you need: - vector illustration with super simple node editing - pantone for print design - simple flash - simple bitmap editing - cool live filters - pdf export Look at their design gallery, some are lightyears better than what other adobe users make....