Short answer - These:
http://www.ebay.com/itm/S-G-Tool-Aid-18980-Master-Ratcheting-Terminal-Crimper-Set-/191305543811?hash=item2c8ab2f083&item=191305543811&vxp=mtrLong, drawn out, meandering answer:
Most of my 30+ years of working for the man have been spent in consumer electronics repair and industrial maintenance with a 3 year stint in electro-mechanical assembly building automated guided vehicles for GM, Chrysler, US Government (MX missile program), and many more. I've used every type of crimper imaginable from the cheapest sub-dollar to top shelf (Molex, Amp, TE, etc.) and crimped tens of thousands of various styles of terminals. Yes, the top shelf crimpers will make high quality consistent crimps for thousands of terminals without any issues provided the OEM terminals are used, the wire end is prepared properly, and the operator is qualified. The down side is they are typically very expensive and are usually specific to a few sizes of 1 style of terminal. Great for production, sucks for maintenance and casual uses like many here. For most of my life I used Thomas & Betts version of the Klein crimpers that Falcon69 pointed out. That style worked great because the jaws are over 1/4" (8mm) thick so most or all of the connector barrel gets swaged. They also have the 'tit' that sticks up in 1 jaw that really locked everything in place well making it difficult to mechanically pull the wire out without breaking. There is also a lot a variability in the size/thickness of both the barrel and the insulator between different brands of insulated terminals for the same color so a pair of crimpers that may do a decent job on A brand terminals may not do so well with B brand etc. so having the 'tit' helps assure a decent crimp on most brands. The caveat is that the 'tit' will often puncture or break the insulating sleeve around the barrel which could pose a safety issue which is why at some point they stopped selling that design for insulated terminals, designating them for use with un-insulated terminals only. With that in mind, they were great for personal use but not acceptable in the industrial environment at work.
So I started sniffing around the net for a proper set of ratcheting crimpers for use at work that not only crimped the barrel, but also the insulation where the wire enters the connector. It's important to crimp on the insulation to help spread any stress on the copper over a larger area. If this step is skipped then mechanical stresses tend to concentrate right at the point the copper enters the metal portion of the connector and can work harden and break under moderate vibration. I work with a lot of different types of terminals so I wanted something that used interchangeable dies as well. I ended up purchasing this Tool Aid #18980 set off Fleabay for just under $100.00. It uses standard size dies and have a handy quick change die feature so you can swap out the dies in under 30 seconds

. This set came with 9 sets of dies that covers a pretty wide range of connectors. There are 3 different die sets that cover most red/blue/yellow insulated connectors, 1 die for uninsulated connectors (4 sizes), 2 sets of dies that cover Weatherpack terminals and it looks like they'll work for Mate-N-Locs, Molex, and other connectors with that style of terminals. There's a die to do red and blue flag terminals, a hex die for RG-6/58/59 etc. coax connectors, and finally a die for preparing 8mm spark plug terminals. I also purchased a die set for 15, 30, and 45 Anderson Power Pole connectors off fleabay for $15.00 shipped which was a very nice bonus.
Another tip for using insulated connectors in harsh environments (automotive, marine, industrial, etc.) is to pack silicone grease (I buy it local at the auto parts store) in both ends of the connector after it's crimped then slide heat shrink tubing over that and shrink it down. The silicone grease will prevent moisture from getting into the connection and the heat shrink not only protects the connection and keeps the grease in, it also acts as a strain relief reducing the chances of work hardening and breaking of the wire. It's also very inexpensive compared to buying them with the tubing and adhesive.
The same crimp tool will do both, if you use what most electricians do. A pair of side cutters.
Most of the electricians I've worked with are utter hacks so that doesn't surprise me. The dollar store crimper jaws are probably 2mm thick and they don't properly swage the connector so let's use something that's sub-millimeter in width to make sure the connection is ever worse

. That's OK, just wrap it with half a roll of electrical tape and she'll be right. Actually, the 2 'electricians' I work with would never use a crimp connector. They just use a wire nut and tape to spice in the replacement prox. switch 2" from the body so it's exposed to oil and slightly corrosive coolant which gets wicked up the cable into the body causing the switch to fail again. No offense intended to all the very sharp, qualified electricians that are out there as my sample size is very small at about 6 or 7. There's currently 2 in our department and that will likely drop to 1 at some point because it's a matter of time before the other one kills himself doing insanely stupid crap like hooking his handheld oscilloscope straight across 2 phases on a live 480vac 1000amp bus duct

and then 'schooled' me regarding CAT ratings when I tried to explain to him how incredibly stupid and dangerous that was

. When I asked him if the both channels on his scope were fully isolated from each other he retorted that I was just being an arrogant asshole because I was jealous of his scope

.
Last week I found issues with 2 of the 3 power factor correction units in our plant. Neither of the 'electricians' had a clue what they did or how they worked. To be fair the other 3 'non-electrician' technicians including the boss didn't have a clue either. Then I did something really stupid - I tried to explain capacitive and inductive reactance, real power, apparent power, etc. to the group

. For those wondering, I'm currently an industrial maintenance/CNC technician for a mid sized machine shop (about 100 machining centers). And yes, I think what a bunch of pus**es when you guys freak out about any voltages over 30v
