I usually only buy the magical items and +hp/mp armors when I see them at a good price in a bazaar.
For example an LS member has been pricing Seers Tunic for while now and its been running about 25-30k in all the AH I bought It for him for 16k in a bazaar in sandy....

So yeah I like to go with the +hp/mp stuff only if I get a good deal on it