Tom,
1st off. dont "think" magic items when making a list

, you should be "focussing" on two points
- army breakpoint
- staying in points
in a lot of situations you could face random magic items, or other restrictions. In general just build your army without them, and then use the items to use up remaining points. And trust me, in more then half the games I play(ed) I tend to forget to "use" my items anyway, other then the always handy "dispell scroll".
So when you go for a set number of points
- know what units you have at hand
- know which min/max you need to follow
- take all the mandatory units and characters, and then figure if you have enough command nodes, if not take more if you can
- fill up the remaining points with available units that suit your style of gaming, and consider that it is always
better to end up with an
odd number of units.
and ALWAYS make sure you take your favorite unit !!