One way to beat slugs is to plant things they don't like.  This would include plants that would likely irritate their slimy little bodies such as plants with hairy or rough surfaces, fibers, sap or plants that are very aromatic or have thick, leathery leaves. 

I have collected this list from books, websites and experience.  I welcome your feedback: info@daytonnursery.com
 

Perennials, Grasses & Ferns
Alchemilla mollis, Lady’s Mantle
Alstroemeria, Peruvian Lily
Armeria, Seathrift/Sea Pink
Artemisia, Silver Mound/Wormwood
Aquilegia, Columbine
Astilbe, Feather Flower
Aubretia, Purple Rock Cress
Bergenia, Saxifraga
Cerastium, Snow-in-Summer
Cheiranthus, Wallflower
Crocosmia, Montbretia
Dianthus, Carnations/Pinks
Diascia, Twinspur
Dicentra, Bleeding Heart
Digitalis, Foxglove
Echinacea, Coneflower
Echinops, Globe Thistle
Epimedium, Barrenwort
Euphorbia, Cushion Spurge
Ferns click here for more info on varieties
Geum, Avens/Grecian Rose
Ornamental Grasses click here for more info on varieties
Geranium, Cranesbill (Hardy Geranium)
Helleborus, Lenten Rose
Hemerocallis, Daylily
Heuchera, Coral Bells
Iberis, Candy Tuft
Lamium, Spotted Dead Nettle
Lavandula, Lavender
Leucanthemum, Shasta Daisy
Nepeta, Mint
Oreganum, Ornamental Oregano
Penstemon, Beard Tongue
Phlox subulata, Creeping Phlox
Phlox paniculata, Garden Phlox
Polemonium, Jacob's Ladder
Pulmonaria, Lungwort/Bethlehem Sage
Rudbeckia, Black-Eyed Susan
Salvia, Meadow Sage
Santolina, Lavender Cotton
Scabiosa, Pincushion Flower
Sedum, Stonecrop
Stachys, Lamb’s Ears
Verbascum, Mullein
Veronica, Speedwell
Vinca minor, Periwinkle/Myrtle

Bulbs
Agapanthus, African Lily
Allium, Ornamental Onion
Hemerocallis, Daylily
 

Hardy Shrubs & Vines
Rhododendron x Azalea, Azalea
Camellia, Camellia
Vitis, Grape
Ilex, Holly
Hydrangea, Hydrangea
Hedera helix, English Ivy
Potentilla, Buttercup Shrub
Rhododendron, Rhoodendron
Viburnum, Viburnum