This post is gonna make it pretty clear that I have extensive and intimate experience in manscaping, and it will get somewhat graphic. You've been warned. Summary is at the bottom.
I'm not gonna comment on legs because I have no experience shaving legs.
As for manscaping, though, I've been smoothing the bush out 2-4 times a week for 10 years. Here's my experience:
If you actually care to get a CLOSE shave and not just a trim down to stubble, then disposables and cartridges are absolutely the worst possible option once you've gotten the hang of other options, or if you've got the money to spend on waxing/sugaring.
A DE shave can get really close and smooth, but it gives me ingrowns REALLY bad. I get a great shave on my face with my DE and am thrilled with the experience but down there, the hairs are just different, and I spend 1 day with beautifully smooth skin down there and then 2 weeks with horrible red bumps everywhere. Believe me, this is the worst possible result if you care to have an active sex life, or general comfort, or...a lack of ingrown hairs. If I ONLY make a WTG pass with my DE, I can get a stubbly trim down there with no irritation. But the XTG pass on that area does NOT have the same effect as on the face (further reducing stubble). For me, an XTG pass does nothing until it's closer to an ATG pass, and once it's that close it shaves very nicely but leaves me with ingrowns for weeks. You may want to give yourself a chance with the DE if you have experience using a DE properly and know that your skin is not generally prone to ingrowns. See for your own skin whether you can get a smooth, sustainable shave down there without suffering the same consequences. But be warned - it will take a month for your skin to recover if it's like mine.
By far the best option is to just get a Brazilian done if you are looking to be fully smooth. Unfortunately, this is probably not available in a lot of areas, and it's generally pretty expensive. If you want to cry about the pain then all I can say is, either man up or learn to be a masochist. I get some ingrowns from waxing but fairly few with proper exfoliation and moisturization, and usually those particular ingrowns are mild and come to the surface quickly. They tend to just grow straight and only under the very top translucent layer of skin, whereas the ingrowns I get from shaving too close grow curled and deep under the skin, causing big bumps.
Finally...balancing price, availability, closeness, and irritation, the absolute best option I have found is to use an electric with the right foil. For the private area, the right foil is one that contains a fine circular-pattern mesh and ZERO slits. Here's an example of a good one:
http://static.howstuffworks.com/gif/shaving-11.jpg - and here's an example of a bad one:
Cordless electric razor / shaver (Foil head razor) | Flickr - Photo Sharing! . Also, I've found that Panasonic electrics perform much better than other brands. The electric gets a decently smooth shave (considering where you're shaving), it can be used every day, it almost never causes ingrowns, it never causes irritation, and it's cheap and available everywhere. It may sound challenging to perform the task, but you can absolutely maneuver your electric correctly and get a good shave on nearly EVERY part of your man-bits if you work at it. There is, however, one important exception. DO NOT USE AN ELECTRIC ON YOUR SCROTUM, EVER. Luckily, for that area, any manual razor I have is fine down there - the skin's pretty tough, it just takes a lot of awkward pulling to make sure it's taut and avoid nicks. But even a dull rusty disposable with zero lubrication will be fine on my boys as long as I pull the skin taut.
If you happen to put a lot of effort into shaving your entire intimate region, including your coin purse and perianal area (yes, you're doing it blind), then just be REALLY careful never to shave side-to-side over the seam that runs from your scrotum to your anus, because it gets cut really easily and you really don't want to get an infected nick down there. Use a cartridge or disposable for it, since the head of a DE is too big to maneuver in those hard-to-reach areas. Again, the skin's tough there, so you probably don't have to worry about irritation.
I have no experience with straights and probably would invest in permanent laser hair removal before I'd ever use a straight down there.
Summary of my manscaping post for those who want to keep their intimate area smooth in general:
- Get a professional Brazilian done if you have the money, can find an experienced professional, and aren't too much of a sissy to deal with the pain.
- Barring that, use an electric with the right type of foil (only circular mesh, NO slits) for the proper balance of cost, irritation, closeness, and availability.
- Give a proper DE shave one try, but be warned that you may get awful ingrowns if you manage to get a close shave with it. If you don't, this is your best option.