The system I built for myself is an i5-based quad core. It does everything I need it to do in Lightroom 4.3 and Photoshop/Premiere Elements 11. I have done a few basic video edits, but mostly stills. Not doing too many complicated things, but I have noticed most PSE processes, with a few exceptions are single threaded.
CPU) 3570k overclocked on air to 4.3Ghz. aftermarket air cooler, but it isn't anything spectacular (used CPU didn't come with heatsink), although probably is slightly beefier and fan is slightly more robust than the stock unit. I run the fan at 35% under normal conditions, which is just barely audible if you really try, and target temp at 70-deg C. Fan rarely kicks up, usually only when I am making sharpening/NR or other real-time slider adjustments. The chasis is semi open-air (gaming case) and I probably hear the GPU fan more often.
Disks) my boot/OS/app drive is a newer SanDisk Extreme, which gets close to 500MB/sec r/w speeds (real word speeds). Apps are here, LR catalog is here, scratch is here (probably shouldn't be since it may be decreasing the life of the drive, will probably move to a striped HDD RAID-0 config). Original pic files (jpg mostly/ some raw) are on mirrored (RAID-1) slow-speed drive pair (75MB/sec), but seems to not hold me back too badly. I may change this to a RAID-5 at some point, but so far don't have the need.
RAM) considered going 32GB originally, but only bought 16GB (2x8GB) of PC3-1600 and it seems to be enough. if I have EVERYTHING I possibly can open (LR, PSE with 5 open projects, dozens of browser tabs with flash and java apps, XP-Mode VPC, video capture app, etc, etc) I get to 70% used.
Power consuption) idle, the system (using integrated video and single drive config), draws 25-30w. another 20w for the add-on GPU. a few watts per platter-based hard drive. No real heat comes off it anywhere, but may be largely because of the already good airflow the gaming case provides.
Like I said, it is handling everything I need to do very nicely. Big upgrade from my 4yr-old Core2Duo system. All-in cost, for the case, CPU, RAM, SSD, INCLUDING reused GPU/PSU, but NOT counting reused extra HDDs, was right around $550.
You can spend the extra $100-125 on a 3770k, but I'd recommend only maybe if you are doing a lot of video encoding that can take advantage of the 4 extra threads. Also, I know a lot of people like to spend oodles of extras on the latest and greatest fan/water coolers and other gadgets, but when the equipment is rated to run hotter, why not let it, and keep your $$$/performance lower?