Need help picking EPs for new scope

Just purchased my first serious scope, a Borg 100mmED refractor(semi-apo) and now need to pick out some eyepieces. I'm not sure I understand how the focal length of the telescope plays into the decision of which EP to buy or if it's a factor at all. For example, does this have anything to do with whether or not one choose a wide angle EP or not? Initially, I will be viewing the moon, planets and whatever else I can find from a suburban St. Louis location. Not ready to go all out yet, but willing to spend in the $50-80 range. Would start with 2-3 EPs and a Barlow. Any advice regarding types, sizes, brands to get me started would be much appreciated.
Thanks in advance.
Jim

University Optics orthos are great simple eye pieces good fov and eye relief, economical and real easy to resell if you decide to go a dif direction they disapear off astro mart almost as fast as they come up, to determin magnification devide focal length of eye peice into focal length of scope ie if your scope is an f8 it will be 800 mm long a 10 mm eye peice will go into that 80 times wich is 80x magnifacation. and a barlow will efectivly double the number of eye pieces you have, do your math though an 18 mm eyepeice behinde a barlow becomes a 9 mm etc so don't buy a 9 and an 18. john

Jim - The focal length of your scope is quite important when choosing eyepieces. Your scope has a focal length of 640mm and to determine the maginfication you will get with an eyepiece divide the scope f.l. by the eyepiece f.l. ( eg, 640 / 16mm = 40 x ). The practical limit of magnification for most objects with a given scope is 50 to 60 times the aperture in inches. In a suburban location like yours, the lowest useful power on the Borg scope would be about 20x (32mm eyepiece).
University optics eyepieces are generally accepted to offer the best "bang for the buck" so I'd suggest starting with them. I would go with a U.O. 16mm Konig, 12.5mm ortho, 9mm ortho, 7mm ortho and a televue 2.5x powermate. That would give you a sequence of powers from 40x to 228x with no major gaps. I suggested the powermate since it is generally accepted that it is a superior design to conventional barlows. If you need to wear glasses while observing or prefer a lot of eyerelief, the Orion ED-2 series would probably be your best option. Also, if you don't already have one, it is a good idea to invest in a quality 2" mirror diagonal. Here is a link to a good explanation of magnification:
http://cloudynights.com/howtos2/magnification.htm
If you can, get out to a local star party and look through various eyepieces to see what you like best. Sometimes, if you are polite and offer views through your scope in return you may be able to borrow eyepieces to see how well they work.

Clear Skies,

Joplin

btw, www.universityoptics.com, is a place to look at, i've been pretty satisfied with their 2.8 klee telenegative amplifier, the guy is real nice and very helpfull some times its a little hard to get a hold of him but keep trying, the price is right to. john