Hi Andrew,
For new ones on a budget you could look at
www.andrewscom.com.au.
Alternatively secondhand ones, the 'for sale' areas on:
www.astromart.com or
www.cloudynights.com are worth watching.
Huygens (H) or Ramsden (R) eyepieces should be avoided, both are very antiquated designs and virtually anything else will be better.
Konig/Erfle - stay clear of these, too;
Kellner - very old design, OK for 25mm but a Plossl is better;
Edmund RKE are all fine, 8 - 28mm;
Vixen LV, NLV or LVW eyepieces are all fine; the only difficulty is finding these - people rarely part with them - these have very long eye relief and are very comfortable to use;
Plossl, esp 15mm or longer focal lengths,
"Symmetric' is another name for a Plossl eyepiece (see above)
Orthoscopic (often labelled 'Or') are fine, esp for short focal lengths though very little eye relief;
Anything from TMB, Pentax or Televue - all excellent premium eyepieces.