Hi. I stayed at Tauch Terminal 3 years ago. It is 3-star, fairly reasonably-priced and has a pool, good dive-op on site. The restaurant is so-so but fairly cheap (lunch for US$3-4). They can also arrange for other activities/trips (more on these later). Most of their guests are Europeans (French and Germans) who are on month-long paid vacations (made my very jealous). The dive op employs Australian senior instructors, but the majority of the instructors, DMs, and staff are locals and are very friendly. They even have local women carry your gear to the entry point for shore dives - I like this because I see my money going to support the local community. Most of the staff speak some English and a major plus is their location - right on the water and the Liberty wreck. Diving with them is fairly reasonably-priced (+10% discount if you bring your own gear) and offer different dives: the Liberty wreck, shore dives (many dive sites accessible from shore) and boat dives (Blue Lagoon, Nusa Penida, Nusa Dua, Amed etc).
But if you're looking for a more exclusive (better service, fewer guests), I've heard good reviews on Seraya. I'd also like to recommend an even more exclusive Villa Agung Bali Nurwana (I stayed there 2 years ago), which is 15 mins drive to the west (on the way to Singaraja), transportation to/from Tauch Terminal can be arranged. This is more than a step up from Tauch Terminal - very good service, great chef, and off the touristy path. It is very private (no chance of being bombed by terrorists), eco-sensitive and yet luxurious (you have your own villa), and have their own beach and house reef. Their website is:
http://www.agung-bali-nirwana.com/
Also, there are many activities which you and your GF can do aside from diving. These include spa/Balinese massage, shopping for arts & craft at Ubud (carvings, masks, furniture, paintings, woven/painted fabrics, jewellery etc), visiting waterfalls and temples, climbing hills and valleys, watching traditional Balinese dance, tasting exquisite local dishes such as Babi Guling (BBQ pig) and curries etc, all of which can be arranged by your hotel/resort.
Have a great trip.