Having just bought one (and extensively researched the market) I'll have a go:
What specifically are you looking for? Are you after a Gen 1 or 2? 4WD, S, Manual/auto, options etc etc.
At the moment all 996/997 911 prices are on the up regardless of model when compared to 1-2 years ago. At very worst the tatty high milers are holding steady and there are very few true bottom end 911 bargains around anymore (i.e. <£10k 996). Any low mileage, low owner 911 will hold its value. If you want to spend less than £30k there are plenty of options, but IMO these are likely to fall long term rather than hold steady. There's a pretty stark contrast between cars >50k mileage and >4 owners and those with less than this. Even so, there is definitely a floor price which is on the up regardless of model due to general brand residuals and image doing very well. We can thank the ridiculous pricing of the RS cars for that! In terms of whether you should spend less, that depends on what you want to do with the car. Is this a keeper/dream car or are you likely to want/need to change or upgrade in the future? Are you after a bit of a project? Would you modify etc? The 996 and gen 1 997s are either at or approaching the bottom of their depreciation curve, so even if you lose money, you won't lose it quickly with normal use. If you're keeping the car long term, residuals become less important anyway. In terms of price, I think the gen 1 and gen 2 997s will slowly start to converge in price as the low mileage examples and the high mileage examples sort themselves out over time. Gen 2 will always be more expensive due to the fact that it'll be a newer car. Will the price fall through the floor - unlikely. Any car can suffer depreciation if lots of miles are put on it or it's involved in an accident.
When you're looking, be as open as possible to all cars regardless of colour of specification. This will broaden your search and get you a better overall car. If you're after a yellow manual 4S with electric sports seats and ceramic brakes you need to be prepared to wait and might be waiting forever! My criteria was pretty much any 997 which I could afford which was a manual convertible with less than 50,000 miles. Much as I would have liked a gen 2, my budget wouldn't stretch. The difference in outlay is the cost of a full engine rebuild at the moment, so I couldn't justify finance or other creative accounting at this stage. I got a pre purchase inspection and I would do it again were I to buy another. If you're looking at a gen 1 there are engine issues, but whether you'll be affected and whether this justifies spending more on a gen 2 at the start is up to you. Having a low mileage example gives me peace of mind with regard to residual value and also general component wear. This has been validated by my trip to Center Gravity (more on that later) which has returned a glowing report for the car (apart from a £40 inner rod end).
Living with the car is (in my short experience) excellent. It's easy to drive and a real occasion to do so. Servicing is fixed price at most specialists and parts aren't crazy expensive for consumables. If you're used to running a high performance car then it shouldn't be too much of a shock, it's definitely not in the realm of exotica. My only comment on your short journey to work is that it's very important to allow the car to get up to temperature. The gen 1 cars especially hate short journeys and score the bores as a result of not being warmed properly (or that's the theory). You can warranty a 997, but I'm not going to bother as the up front cost of getting the car fit for it in my case is 4 new tyres, a major service at Porsche, the 111 point inspection and removing my bluetooth kit. Plus the cost of the warranty that seems like a lot of cash to put in the bank for a rainy day. A PCM upgrade is definitely on the cards for me, so again that would render the car unsuitable for warranty.
Enjoy your search and go drive a couple. If you spot a good one, put a deposit down and get it inspected, as they don't seem to hang around. I did this without seeing mine in the flesh, but it seems to have been worth the risk!