Allow me, as well, to sing the praises (and dirges) of MapTool.
Generating battle maps in MapTool is worth the learning curve. RPTools also has video tutorials that walk you through the basics, and that makes up for a lot.
For basic maps, don't spend time making your own. There are plenty of free maps out on the web that will fit your needs and you can usually google them by category. These can easily be imported and gridded in the MapTool environment.
You can add objects and artwork in *png format from any other source (the forums at Dundjinni, Cartographer's Guild, etc... are great for getting free art and ideas).
The real power of MapTool, however, is that it's a full programming environment. You can reveal the map only from the PC's point of view (line of sight/effect, etc...) while maintaining content from the DM's point of view (traps, secret doors, hidden monsters, etc...). This capability is called "Fog of War", and it's way cool.
There is actually a
forum thread in the community site that has macros for 4E rules, allowing a full game to be played online in real time. I tried it, but you have to be a super computer programmer to really take advantage of it. Way too much time IMO.
If you want to create your own maps, PSE (PhotoShop Elements) is a really cool (but expensive) tool. Dundjinni and Campaign Cartographper are neat and less expensive, but at the end of the day they rely on you to have PSE if you're going to make real eye-popping battle maps.
Here's my strategy. Start with free stuff (gimp instead of PSI and MapTool for generating screenshots of your map). If you want to get fancy, get PSE to make walls, objects, etc... more realistic. Then if you want some
really fancy looking dungeons or overland maps get CC and/or Dundjinni. Beyond that is way too much time and money invested IMO.