Here's the list I'm using with my current career save that I've found to be pretty fun, and a brief note about why I'm using each, and categorisation. Play on hard mode and don't use admin building strategies (since they're currently incredibly unbalanced). Career mode with this mod set, I've found, is pretty difficult, but with a really rewarding feeling of momentum and persistence. You will also NEED active texture management or the game will crash on loading, unless you can play in OpenGL mode without problems (which is what I'm doing, and it's saved me a lot of memory). Several of these mods are not compatible with 64bit, so don't use 64bit. Pre-reqs/Quality of Life/Utility These mods are either required for some other mod I use, or just generally make the game much more friendly to play. Blizzy's Toolbar - Because it's required for various other mods. Kerbal Engineer Redux - Eliminates a lot of the guess work regarding whether or not you've got enough fuel or a high enough TWR. Playing on Hard, this is pretty essential, since repeatedly prototyping large craft is prohibitively expensive. Kerbal Alarm Clock - Useful for not over-shooting maneuver nodes and keeping track of when you need to send care packages of life support. Also useful for getting a rough idea of transfer windows to other planets (although there are much more accurate and customisable mods you could use for that if you wanted. KAC is good enough for me.) Kerbal Flight Indicator - Rarely actually use this, but it's very useful for landing spaceplanes. Basically adds a simple overlay on the game view showing the horizon, your heading, and your prograde/retrograde markers. Trajectories - Shows you where you'll land on a planet, taking the atmosphere into account. Plays nice with FAR. Useful for returning near the space center. Parts/Gameplay Mods This is the real meat of the career experience I'm having. FinePrint - Adds much more interesting and varied contracts. Going to be stock soon. Deadly Re-entry - Makes planning descent trajectories much more interesting. Or you can just slap on a bunch of heatshields and call it a day, if you're boring. Can be a real pain and feel pretty limiting at times, so you may want to skip this. TAC Life Support - This is one mod where I can never decide if it's worth it. On the one hand, it adds an additional level of planning and adds to the challenge of building stations/bases. On the other hand, never running out of life support sometimes feels trivially easy and like it's just busy work, and the mod clutters up the parts tabs way more than seems reasonable. But I am using it for the time being. Ferram Aerospace Research - The famous FAR. Can't imagine playing with the stock aerodynamics anymore. Feels like it makes the game a lot harder at first, but actually makes a lot of things easier once you're used to using it. You could use NEAR instead if you want a somewhat easier but otherwise similar aerodynamics model. Or you could use stock aero if you're happy with that. Whatever. Kerbal Attachment System - Bring along a toolbox with some useful bits and pieces, and maybe save your doomed missions with some quick thinking! RemoteTech - Unless you use MechJeb, I'd strongly recommend turning off signal delay (simple .ini edit). Interesting mod because it requires you to deploy and maintain a satellite network if you want to send unmanned missions or transmit data. A lot of people might feel like it adds too much busywork, but I like the extra feeling of persistence from having all those satellites flying around. SCANSat - Biome maps! Cartography is fun! Station Science - Long-term science experiments peformed in orbit. Gives a nice purpose to building space stations. Adds to a feeling of progress and persistence. Includes contracts! RealChute - Actually considering getting rid of this. I'm having a really hard time using it with DRE and FAR, but I think it's my own lack of expertise with configuring the parachutes properly. Gives you lots more options for parachutes. KW Rocketry - Adds a bunch more options for engines/fuel tanks. I like options. DMagic Orbital Science - Adds a bunch of new science instruments for collecting moar science. Doesn't feel OP or anything like that. Procedural Fairings - The KW Rocketry fairings are just too small a lot of the time, so I have this installed. Although the KW rocketry ones are a lot prettier, so I use those when I can. Modular Kolonisation System - Adds planetary/orbital bases and related contracts. Again, adds to persistence, and making bases on other planets is a fun endgame challenge. B9 Aerospace - I've actually removed this, but I'm including it in the list. It adds some parts that are really nice and very useful. On the other hand, there are also a lot of parts I don't like and it does add a LOT of parts, so there's a pretty big cluttering effect. I ended up feeling like the downsides outweighed the good stuff, but there's a good chance you'll like it more than I did. Graphics Enhancement These mods are purdy. Astronomer's Visual Pack - Because it's so pretty. EnvironmentalVisualEnchancement - Required for Astronomer's, adds clouds and city lights and nice stuff like that. CollisionFX - Considering getting rid of this actually. It's a bit buggy. But the effects ARE nice. Distant Object Enhancement - It's nice seeing far away planets. PlanetShine - Very nice lighting enhancements. Venn's Stock Part Revamp - Texture/model replacement for stock parts. I seriously think this should become stock. Keeps a very similar style and feel to the stock game, but looks much nicer. Chatterer - Actually an audio mod not a visual mod, but it doesn't get it's own category. Nice and atmospheric sound mod.
Woop woop woop. As somebody who's really interested in seeing the management and career aspect of the game being more fleshed out, my hype levels are considerable for this release. But can it will be all I imagined and more? I must ride this train through time and space to discover the answers.