Fun combinations of magic items...

[VoodistMonk]

Anyone have any particularly interesting combinations of stacked magical items? Like adding the effect of a Ring of Sustenance to a Ring of Evasion? Or even neat uses of special materials?

I like to combine a Minor Ring of Spell Storing with a Ring of Spell Knowledge IV... it allows you to store up to 3 levels of spells and to learn a 3rd-level spell not otherwise on your list. It can be a Bard's best friend.

Or Sunsilk Quilted Cloth Armor for DR 3/- against projectiles, and DR 2/bludgeoning against melee weapons! There is also Sunsilk Ceremonial Armor for 0 ACP and 0 ASF chance, WITH the DR 2/bludgeoning against melee weapons... it's almost like real armor, but for arcane casters. Lol.

I really like Angelskin Shifting Jerkin for certain applications... the hiding alignment aspect of Angelskin and the at-will Disguise Self part of Shifting Jerkin seem to go well together.

[Ryze Kuja]

Boots of Speed + Boots of Striding and Springing

Portable Hole + Bag of Holding = Black Hole Arrow

[zza ni]

goz mask + saltspray ring.
if you can sneak attack add sniper goggles and full attack sneak from any range.
-extra bonus if you can fly which bring into being the next pair:

Lightning Gun and Helm of the Valkyrie.

combine all 4 (or 5) and you have something real nice...

[VoodistMonk]

Here's a good one:
Soultether Ring + Ring of the Faithful Dead... the Soultether Ring keeps your soul from traveling to the Boneyard for judgement, and the Ring of the Faithful Dead keeps your body from being raised as Undead... the Soultether Ring is the primary, since it is more expensive. Adding the effects of a Ring of the Faithful Dead at 1.5x cost isn't so bad. One ring to protect both the body and soul for 4750gp [to craft]... a phylactery for the living.

This one is a little more expensive, but it is great to give to Witches:
Cauldron of Resurrection + Cauldron of the Dead... you can cook people in so many fun and creative ways with this thing! Lol.

[Java Man]

Making a shatterspike out of adamantine, to sunder all the things.

Combo boots of the cat with striding and springing. For those times you miss the ledge you were jumping for.

[Temperans]

Bag of holding + gate rings. You can insert the bag of holding into itself, creating a traveling portable hole that has a fraction of the weight of a standard bag of holding.

On a related note, bag of holding of bag of holdings, depending on GM ruling. Under both rulings the items inside the inner bag are inaccessible. But under one of the rulings the weight of the inner bag stays the same, thus creating an effectively infinite storage space as long of bags inside bags inside bags.