there's plenty of good west coast g shit besides dre, although most of it is pretty difficult to buy in the uk.
if you're looking for that lush g-funk sound, the best producers other than Dre are DJ Quik (check his first 3 solo records, plus the Penthouse Players Clique, 2nd II None, & Suga Free records), Above the Law (everything they did up to Time Will Reveal), Prodeje (the Havoc & Prodeje records, the first 2 South Central Cartel albums, Murder Squad Nationwide), Warren G (yeah he's a shitty rapper, but G-funk era is a production classic, and check the records he produced for the Twinz & the Doveshack), Daz (the Dogg Pound record & his first Solo). Other notable producers include Hi-C, DJ Battlecat, Tracy Kendrick, WC... many more.
also, don't sleep on Northern Cali (the Bay plus Sacramento/the Valley). a very different sound (much "bouncier" and more electronic) but in terms of number of artists and classic albums No Cal shits on So Cal IMO. it's a shame that most people are only familiar w/ digital underground & the luniz, and that solesides/quannum, hieroglyphics, and hobo junction are much better known in the UK than say, 11-5, RBL Posse, or Cold World Hustlers.
finally, people have been mentioning southern artists like geto boys, ugk, slim thug (who's more new school). a lot of laid back smooth g-shit made in the south back in the early 90s. check out early 90s Rap-a-lot, Suave House, Big Tyme, Cash Money, MOBO, Big Boy releases.