Whatever you can afford you will not regret.
Air Conditioning carries a significant year round weight penalty so unless you spend a lot of time in hot/humid areas you might want to think about that twice.
Otherwise, in my opinions (for my needs in Toronto) :
TKS - 10 One of the primary reasons we went for the SR22 rather than a late model Turbo 310R which would have been our next airplane. Lake effect cumulus and ice in the Great Lakes area can be a real issue. We could have real high pressure glorious sunshine but with NW winds creating bands of WET lake effect clouds maybe only a few thousand feet thick. Sometimes they are icy, sometimes not. At least if we dip a wingtip into a cloud while descending we have some help with the TKS. DO NOT however think of it as anything that will get you there or depend on it. It is no more than an extra option.
Platinum Engine- 5 If you have the money, fine. Otherwise it is still a factory built semi-assembly line engine. Same parts just better matching of parts weights.
Skywatch 10 - We debated on this before and after we ordered. We paid a little extra for Cirrus to install it after the plane was already built. It was likely the biggest single everyday safety of flight equipment value. Flying in a non-Skywatch plane feels weird now!
Stormscope - 8 - Good value for information that could save your skin from flying into a thunderstorm that you didn’t know was in front of you. Less value and greater risk than no stormscope (IMHO) if you think it will help you circumnavigate thunderstorms and get where you’re going.
Terrain Avoidance - 9 if you live in Colorado. Things can get pretty busy and your mind can become pre-occupied flying IFR and next thing you know… Bitchin’ Betty will save somebody’s life.
XM Weather - Don’t ask me about that!
CMAX - 4- As it stands they seem to be just expensive pretty pictures. You still need to fly according to current paper plates and the existing MFD display paints a pretty good picture for situational awareness already.
Very important other things to get are a Reiff Pre-Heat system with engine cover, cowl plugs, BAAM (seriously good stuff IMO) and a wax job with Rejex (despite what the factory may misinform you regarding “fresh” paint.)