i recommend to play Flamestrykes mod as the 1st, the classic, its beautiful, perhaps a lil to easy if you are a "wiz8 professional", therefore play it 1st.
After that check whether you like Deathstalkers mod, it has some significant changes on spells.
Qusaris Lunastralis adds decisive changes in the plot, locations and tons of modern weapons(probably somewhat overpowered).
No matter whether you like Luna, check Reforged 1.1, also by Qusari,
probably the mod with the greatest changes regarding texturing, plot, new monsters, functions
(which were not availble in the editor when the previous mods were created)
White Wolf Mod unfortunaly still has some flaws, not quite sure whether they are of minor importance or gamebraking,
its under steady development, in case you are going to play it, pls check the last pages of the mods
thread Last but not not least to mention DoddTheSlayer mod 2.4 as the actually prolly most difficult (regarding combats)
mod in english language, i think it is the most perfect balanced, i.e. will provide a steady challenge for players with high experience.
Find afaik all mentioned mods and tons of other wiz stuff at our Archivarus`s site:
http://www.zimlab.com/wizardry/
If you speak russian, there are also some interesting mods from russian community
which has its home
here