I guess that was another one of my questions to ask you guys....
Is it worth it to buy the kit w/a 18-55mm when you are going to be buying the 50-200mm too? Seems like there would be some overlapping going on there.
Would it be better to buy the PRIME 50mm w/the tele lens? Or, I guess what you're saying is you like your 18-135 (higher mm) instead of a 18-55mm...right?
Because one thing I will need is a lens that can capture all those inside resort lobby areas, inside ride ques, birthday parties, family holidays, night-time shots, etc. A good lens for indoor or low-light situations....wouldn't that be the PRIME 50mm?
If you go with the Pentax, I would think that the 18-55 & the 50-200 would be a great combination. Yes, you would have a tiny bit of overlap, but that is not a bad thing. Look at my equipment list in my signature below. I have a lot of overlap, and it was intentional. Different lenses fit different shooting situations, and more overlap means (for me, anyway) less lens changes, and more photography. For example, while the 18-135 will be my main WDW lens, I also have the 70-300VR, which will probably be my "walkaround" lens at AK. However, since it starts at 70mm, it can cover some of the ground that the 18-135 covers and, since I tend to shoot at longer focal lengths, that will probably work out fine.
I guess the ideal starting combo would be a "kit" lens, covering wide to short telephoto (18-55 or 18-70), a tele zoom (50-200, 70-210, 70-300, etc), and a fast prime (50mm, f/1.8, usually). Nikon also has a killer lens, the 18-200VR, that covers most everything in one swell foop, and throws IS in for good measure. However, it also has a killer price: $750 list, but goes for around $1K...IF you can find one. The $300 18-135 is my "poor man's 18-200VR" compromise. And, yes, I *much* prefer the 18-135 to an 18-55 or 18-70 due to the added versatility, plus it is such a sharp lens.
BTW, from all I've read, Sigma makes a pretty good 70-300 APO lens that goes for a little less than $200. I own a Sigma (the 10-20 superwide zoom) and, while the optical quality is fine, I'm not thrilled with Sigma's service department, based on a recent experience.
Also, for indoor events such as birthday parties, you can (and maybe should) use flash. In addition to a pretty decent onboard flash, I also have a Nikon SB-800 accessory flash that puts out a lot of light, and is great for such things. Flash will stop action, too, whereas you may not be able to stop action with even a moderately fast shutter speed (say, 1/60 sec). And, you can usually use a smaller aperture with flash, and don't have to worry about color balance, since the flash is balanced for daylight. And, lastly, you would not be limited to the one focal length (50mm) by having enough light (from the flash) to use a zoom. To illustrate, my D50 has *horrible* tungsten performance in auto WB, and only somewhat better with the tungsten preset. Either way, it requires correction in PP; a flash shot would not have that problem.
Where the 50 is going to really shine is in situations like one of the WDW stage shows, like FOTLK, where you either can't use flash, or the action is so far away that flash would not reach anyway.
Hope that's not too much info overload. I went thru this evaluation process for over a year before I settled on the D50 and the lenses I ended up with.
~YEKCIM