I'm wondering what your current favourite effects with a borrowed deck or shuffled deck in use might be.

For me, the following effects could hardly be easier, but can pack a real punch:

Gemini Twins
Untouched (Daryl)
Do as I do
Miraview / Predict pairs (Bannon)
Proximity (Bannon)
Lucky 13
My Way Out of This World (Hass)
One Card & One Card Only (Hass)
Unfazed (Ben Blau ESP)
Search & destroy (Fischer)
Con cam coincidencia (Wilson)
Equivoque force w/ “invisible deck"
Cross Purposes (Bannon ACAAN)