Really enjoyed my weekend in Geneva. Whilst we stayed near the railway station, which was a functional, dull area rather than anything special, both the old town and the attractions around the lake were superb.
Hopefully this info will be of use to
@shackattack
The cathedral is more like a large church, but for 7 CHF, you can walk up the towers. This was great because you get to wander through the roof beams on the way up, and the view from the top of both the lake and the old town was well worth it. We went up the North Tower, which is the one with the best view (I think).
Wandering round the old town was great - lots of cobbled streets with flags overhanging and interesting buildings. The city model on the top floor of the free Maison Tavel museum was worth the visit alone (in fact we went straight up, saw the model and then came straight down).
The Reformation Wall is also a one-of-a-kind - a 100m stretch of carved stone figures and definitely worth a look.
Obviously the Jet D'Eau is great, and we were lucky to be there when there is illumination at night. Also on the lake, it was good wandering out to the lighthouse on the Bain de Paquis. Great views of the surrounding hills and mountains.
Bit of an oddball but I also loved the Frankenstein statue!
The transport system is probably the best I've ever seen - free transport when you stay in a Geneva hotel, so we used the trains to get to and from the airport, the buses and trams to get around and the mouettes (the yellow boats) a couple of times on the lake (saving the cost of paying for a lake cruise). There are no ticket machines on board any of the transports - it's a trust-based system, so as long as you have your pass with you if needed, the whole system just feels effortless.
As expected, it was eye-wateringly expensive: £50+ for 4x cake and coffee at Starbucks; £60+ for 4 McDonalds meal; £100 for 4x pizza and soft drinks. £20+ for a couple of Cokes and a couple of waters. You get the idea.
If we were there longer, we'd have gone to CERN and maybe the nearby Mont-Salave cable car system, so I'd have had no problem filling three days. In fact the prices are the only downside that I can see. It's a really beautiful city.
