I have stayed at Rydges Lakeside on numerous occasions and am yet to be disappointed. The hotel is clean and modern, the rooms recently renovated and the facilities are excellent. The Canberra CBD is within walking distance (about 20 minutes) but more importantly the hotel is a beautiful wander around the lake to the highlights of Canberra including the Library (30 minutes), Portrait Gallery (40 minutes) and Art Gallery (45 minutes).
The hotel staff are excellent and always willing to assist (especially Sascha who mixes upthe best cocktails in Canberra - My partner is addicted to the 'Hudson'). The restaurant and bar are fantastic (make sure you join the free Rydges priority guest club and you get at least 20% off everything).
Overall, in my opinion, it's one of Canberra's best offerings!