Padz,I use a Navman Pin300 pocket pc and its the dogs nuts.
I use the roadnav system that comeswith the gps to get around the U.K and have memorymap on it as well for nav cross country,memorymap is a very good system,10 fig grids,waypoint,eta,distance,speed etc plus the 3d terrain mode that I find very usefull as you can also do a walk through of your proposed route.
I bought mine from these people who have all you may need.GPS
Magellan Sportrak range - very rugged, different sort of antenna to Garmins which means better reception under tree cover/in BUAs, not too many of those bone features you'll never use, and runs on AA batteries.
I use the garmin foretrex, its wrist mounted does pretty much everything and its the size of a swanvesta box.
(this makes it easly concealable from any DS that frown upon the whitemans nav magic)
My one is rechargable from the mains,gives between 7-15 hours depending on use. However they do a battery powered version but I dont think its waterproof.
If this is what you want, why pay extra for fancy features? Garmin eTrex. Plain, simple, tough, waterproof, reliable. Uses 2xAA batteries - obtainable from G1098, though I personally use 2300mAh NiMh rechargeables as they last longer.
You can't put maps on it, but then again, maps aren't available for Gucci GPSs in many parts of the world.
The compass feature only works while you're moving, but why would you need a compass if you've got a GPS?
Mine has survived the dashboard to floorpan drop test 10,000 times and a similar number of swinging-from-the-strap-against-the-window tests. It didn't seem to mind high temperatures (57C ambient and rather more on the dashboard). It has been run over once (but I didn't fancy repeating THAT test).
The only drawback is that you can't enter waypoints in advance from the eTrex buttons.
I have the Garmin GPS 72, which is the updated version of the GPS 12. It's waterproof and tough. Costs about Â£120 from www.globalpositioningsystems.co.uk. Uses AA batts.
Not much to recommend it over the Garmin eTrex basic model, though, other than that you CAN enter waypoints in advance using either the map view or grid refs (up to 10-figure), that it's a rather cool black and that I love the little fecker because it saved me from navigational embarrassment when it mattered.
Don't get seduced by the more tricksy GPS kit out there. So long as you're armed with a map, all you need is what you've started the thread asking for: a grid and the ability to punch in a waypoint and have it show you where you are in relation to it. That said, the GPS 72 has got basic map info built-in for the whole world, so that it will show you where you are in relation to Basra as opposed to Teheran even if you are separated from your map (could come in handy, that).
I really don't rate the GPS12, I had one, and it was very big, heavy and slow to gain a lock on satellites. Was even less impressed when the screen cracked on it whilst in my bergen. Spent the insurance money on a Garmin Geko 201, and am very pleased with it. Nice and compact, tough and very quick. Seems to hold a lock well, even in light forest. Only trouble is the bright colour it comes in, hard to keep hidden from officers, but small enough to easily shove into webbing.
Good luck! Thought I'd mention the Magellan Meridian series - they have been around for a while now but are tough as nails - I used to have one on a handlebar bracket on my bike and it survived many long 100mph plus runs in all weathers and still got me across Europe. Battery life is terrible though, approx 4 hours of constant use with the backlight off - any comments about the battery life on the other models?
I'll weigh in favour of the Garmin eTrex. Although I did buy a cover for that gay yellow it comes in. Battery life is about 20 hours if your not pushing buttons all the time.
Performance in snatches is reduced though, but with 4 or five models in any given convoy there was no clear winner or loser
You can't put maps on the basic model, but with a data cable and the world map CD you can get most of the worlds MSR's on your laptop (I can vouch that most of Basra rural up into maysan MSR's are reasonably accurate - use the road overlay on Google Eart to get an idea), then squirt junctions as waypoints into it. The software also enables you to steal other peoples waypoints (its compatible with all of the etrex series) and input 10figs into it, which is a damn sight easier than using the buttons.
Downside to the cable etc setup is that it adds Â£100 (Â£50 for the cable and Â£50 for the CD) to the initial purchase. Some of the pricier eTrex models come with a mapping function and data cable already, (so if your not catching up like I did) it may be more economic to buy the better model and CD if your looking that way - MSR's on your GPS!
Final tip is to get try them out in shops like blacks, then buy on the internet. If there is a shop that sells GPS below MRP I'd like to know about it. I mention blacks because they have someone around who can demonstrate them and have a reasonable range, from the wrist mounted, through eTrex and the better garmin products and the stalwart Magallan.
All GPSs guzzle batteries so you need to keep them switched off for a lot of the time if you want a single pair of AAs to last you for a decent length of time. If you keep switching off and using only to confidence check then 2xAAs should last for a week in the Garmin GPS 72.
It's a bit of a pain in the arrse having to do that, as it takes about 30-45 seconds to achieve satellite lock every time you switch on (apart from the very first time, which takes about 5 mins). But it's better than carrying a shedload of batts around.
I agree that you're better off trying out various types in person, although I'm happy with the one I bought unseen over the net. I chose the Garmin 72 by ringing the GPS shop (link in my earlier post) and telling them what I was planning to use it for. They firmly advised that the 72 would be best for me. That was three years ago (almost to the day), so things may have changed. It could be that newer GPSs are better at the one thing which the older generation were bad at, namely getting satellite lock when you're in light forest.
But GPS is old tech anyway. Why else are some of the Garmin and Magellan models still on sale more than 10 years old? Imagine if they were still trying to sell 10-year-old mobiles.
If you're heading to the sandpit anytime soon, or know someone there - Garmin GPS72, $75 from your local downtown PX (AAFES). On passing through my sub-unit emptied the display cabinet and bought 'em all.