Heh, I'll add a few things:
The most important thing to remember about telescopes is that the best telescope bought is the telescope that you will use reguarly rather than leaving it in a closet to gather dust!
There are so many things that go into buying a telescope, escpecially a first scope.
What do you plan to observe with it? That is one of the most important questions. If you are wanting to look at planets, comets, solar system objects, then a dobson is probably not the best scope to get. For these things you need a scope with a clock drive; dobsons usually don't have them except for the very expensive types or the ones made by amature telescope makers that really know what they are doing. Without a clock drive, by the time you get the object centered in the eyepiece, it drifts out of view very quickly. This (and getting the object into view) can be very frustrating for a first time telescope user.
The large mirror size per cost of the dobson is not going to help much either. Dobson's usually have a low focal ratio. That is not the best for looking at planets. Usually for that you need a scope with a higher focal ratio. To get the dobson to a level that you can seriously look at planets, you have to "stop down" the mirror .. that is, cut out a circular mask and put it over the opening of the scope, but in that mask make a round hole, off center and smaller than the diameter of the mirror (these can be purchased). That limits the amount of light coming in, makes it a higher focal ratio, and gets rid of the diffraction spikes caused by the spider vanes, all making the seeing better. But then, say you stopped the scope down to 4" -- well, that's like looking at the planet with a 4" scope (refractor) -- you've basically lost all the additional area that other 4" provides to catch the photons! The extra money paid for that extra aperature is not doing you any good.
Also, generally, you cannot use high power yield eyepieces with a dobson. I wouldn't consider buying a high power yield eyepiece for a dobson. Generally, they are made for viewing extended, extra-solar objects like nebulas, galaxies, and the like, with a wide field of view. And objects that you take a causal look at, and move to the next object. If you are going to do any serious study -- in depth looking at "an" object, you need something with a clock drive.
Though a scope with a clock drive adds complexities to viewing. You do have to set it up, and align it with the polar axis, or have computer assisted alignment (more $), where you can point it at a couple of obvious objects, tell the computer what object that is, and then let the computer "internally" know the offset from the polar axis that you have the scope at.
Also, you need to consider where you are going to use the scope at. To get the best views you have to take it to a dark site -- setting it up on your driveway in direct line with the neighbor's night light is not going to let you see too much except for the moon! If you are going to take it out to a dark sight, lugging around a heavy telescope and placing it in your vehicle can be the pits.
A few other ideas you might consider:
1) If you are not sure you will use it much, buy a good but cheap telescope first time. That usually means a reflector (Newtonian/dobson). You may not want to worry about getting a clock drive .. it's extra money. A good cheap scope is the
Orion Fun Scope. This one is only 3" aperature, but there are similar scopes with a larger aperature, maybe up to 4". You can cradle it in your lap and support it against your body, to locate and center objects. It's a natural to use like that. It doesn't have a finder scope though. This is a very good scope for a beginner, one that is exploring if they might like astronomy as a hobbie, and won't set you back the big bucks if you make a mistake. If you find out you do like astronomy, then you'll find out that wasn't a bad investment, and (probably) always cherish that scope. This scope also as a mount/cradle that you can place the scope on too, for better/more steady viewing. It's small and lightweight. You can take it anywhere, on a moment's notice.
2) Consider getting a small Meade refractor like the http://shopping.discovery.com/stores/servlet/ProductDisplay?catalogId=10000&storeId=10000&langId=-1&productId=11810&categoryId=22563&interCategoryId=22516&parent_category_rn=1109&partnumber=610105 . These are smaller aperature scopes, in the range of 2.5" to 4", but they have superb optics, a built in table top mount, built in drive, computer database of objects, flip mirror for astronomical or terrestrial viewing, optional tripod mount. You can also take this anywhere. A good finder scope is an essential option on this scope. Heh, I saw last year that even Walmart were selling these scopes. Most would turn their nose up at buying a telescope from a department store, and I would too a few years back, but these scopes are good scopes. Just be sure that you get what you need to effectively use the scope in the base package, and that the things they are offering as "options" are not actually essential to the operation of the scope.
3) Orion also has a "Short Tube EQ Reflector", that should be looked at seriously. They are quite comparable (usage wise) to the Meade ETX scopes. I noticed this scope has only a small reflect sight. These are good finders for someone starting out .. you can sight what you are trying to look at straght through .. and that is natural to try to do first time viewing. You will quickly move to a finder scope though .. I would recommend a good finder scope added to this telescope, as in the Meade ETX.
