tough-ish question.
modern full suss wise i have an 08 Orange st4 and an 06 patriot 66
i personally prefer single pivot full suspension bikes, purely for the ease of maintenance, multi linkage bikes are expensive to maintain even if you are capable of doing it all yourself, most have 8 bearings and the shock to take car of which are costs you simply don't get on a hardtail and are far reduced on a single pivot bike. so if you do go down the suspension route consider long term costs, ask if the parts are readily available on request, not special order, are they parts that can be sourced several years down the line etc? some brands have great designs that quickly become obsolete.
that said, in modern times i have predominantly bought 6 inch + bikes for trips to the alps then sold them afterwards (this was when i was in the trade) when i finally bought a full suss as a keeper i asked myself where i would be riding it most, home trails and wales, so i decided 4 to 5 inch for the travel. at the time i was just coming to the end of working in the bike trade at an Orange dealer and they had just launched the ST4, their first linkage bike, i trusted that the designers would get it right and one of the main testers i knew so asked his opinion based on what it would get used for from me and he thought it would be perfect for me. so that was that, i got one.
i really like it, i still mostly use it in wales, it's a little draggy on the gravel track climbs but it climbs better than my hardtail on technical climbs and downhill is a blast. the handling is spot on! in 3-4 years i have only needed to change the bearings in the frame once.
my other full suss is a patriot 66, this was designed as a do it all sort of bike by Orange, it could be set up as a 5 1/2 inch bike or 6 1/2 inch (hence the name 66 meaning 6.6 inches of travel) depending on the shock fitted. i have an air shock and a 5 inch fork and also a coil shock and a triple clamp 7inch fork. i got the frame a couple of years ago for a trip to the alps and got lucky with some cheap parts so for a week or 2 of the year it's my downhill bike but the rest of the time it's set up as a 5 inch bike and i use it in wales. again i love the way this bike rides, handling is great, again a bit draggy on the gravel climbs but not so bad climbing that i get pissed off with it and downhills are amazing on it!!
i have also ridden over the years many of the Giant designs, i think their maestro (floating pivot point) design is good but i didn't like the geometry of the frames, i felt the head angles (at the time) were too steep, i also had a Santa cruz heckler, liked it at home but not in the alps, weird that really.
there are some great designs out there though.
personally not a fan of specialized, i used to see them wear shock bodies aswel as go through bearing kits, vpp/fpp bikes (santa cruz blur etc) tend to go through bearings aswel as the linkage parts. also talk to Makster about the lapierre, his mate Paulie has one and has just had an almighty bill for pivot bearings!! some of the scott bikes have such tiny pivot bolts and bearings that they wear the holes inside the frames aswel meaning the frame dies unless you know someone capable of sleeving inside the frame after oversizing the holes! my old boss did that repair on about 8 scotts while i was there!
don't get me wrong i am not trying to put you off getting i suspension bike they are great fun but be aware they will cost more to run and on that basis i would recommend a single pivot bike, orange, santa cruz superlight or heckler, something like that.
also try and get to demo days, there are loads around the country this summer, free bikes for a day usually in good places to ride and YOU don't have to clean the bike afterwards!!
hope that helps a bit
