These days I only use my tent when car camping and sometimes when canoeing.
For backpacking I just use a silnylon tarp that weighs a few ounces.  I also
bring an OR bug bivy if I expect bugs.  This gives almost all the benefits
of a tent with much less weight.  Area under a tarp is much larger than a tent
and the ventilation is better too.  Only drawbacks are that it is much more
difficult to pitch a tarp, and a tarp doesn't handle high winds nearly as
well as a tent.

My tent is the Eureka Mountain Pass XT -- Two pole dome tent.  Sleeps two,
two doors each with a vestibule.  37.5 sq ft + 16.5 sq ft total in the two
vestibules,   Floor 5'x7'6", center height 3'6", packed size 5.5"x16"

Mine is the 97 or 98 model.  Newer models have a peak vent and plastic
window in the fly.

Weight (as measured by me):
  body + fly + stuff sack    4 lbs 7 oz
  high alloy aluminum poles  1     2
  ground cloth               0     4
  other                      0    12
  -------------------------  -------
  Total weight               6     9

The 4oz ground cloth is 2mil plastic.  You can buy huge rolls of it cheap
at a hardware store (look in painting supplies for a drop cloth).  The
ground cloth that Eureka sells weighs 10oz and costs lots of money.  Don't
buy it.  The "other" category includes 12 stakes (I bought nice aluminum
stakes to replace the lousy Eureka stakes), 4 guy lines (about 8' parachute
cord each), stake sack, seam sealer, and an aluminum pole repair sleeve.
Carrying the seam sealer is probably useless.  Just do a good job with it
at home and you won't need to make repairs in the field.

For what it is worth, I never carry or use the ground cloth these days.  The
tent does just fine without it.  If you do decide to carry a ground cloth,
be sure to trim it smaller than the floor.  If the ground cloth sticks out
it can collect rain water and funnel it under the tent.  Some people keep
the ground cloth larger than the tent, then fold all the edges back under
to keep it from collecting rain and to help funnel surface water under the
ground cloth.

I'm pretty sure that most of the good Eureka tents are seam taped these days.
If not, you will need to seam seal the tent.  Don't buy the Eureka or Kenyon
seam sealers.  Get McNett seam grip.  Be careful with it because it is tacky
even when dry.  A light dusting of baby powder or something similar will make
it less sticky and keep your tent from getting stuck to itself.  You do need
to make sure all the seams in the fly and floor are sealed.

Don't get the "gear attics" that Eureka sells.  They cost too much and take
up headroom.  I used the attic attachment points to put a clothesline in
my tent.  Took parachute cord and tied it through the loops with a double
fisherman knot so the tension could be adjusted.

I've been happy with the tent so far and find setup to be pretty easy.  Done
it in the dark many, many times now.  The new Eureka Exo series looks even
easier to setup.  My tent doesn't seem like the toughest tent in the world,
but it hasn't failed yet even after quite a few nights overstuffed with
two cuddly people and two dogs.  It has never leaked through some pretty
serious rain storms (I was meticulous when seam sealing and have repeated
the sealing every year or so).  The tent probably has well over 100 nights
of use on it and has stood up well to dog toenails and dogs banging their
heads against the doors in a futile attempt to go in or out.  The vestibule
is cramped if you have to take off raingear in it, but is very large for gear
storage.  The fact that you have two doors and two vestibules is a huge bonus.

The biggest annoyance is that when you unzip the fly it drapes against
the tent and gets water inside.  Perhaps that wouldn't be a problem if
I were more careful, but it always seems to get me.

I paid $120 for mine brand new at the Eureka outlet in Binghampton.

Whatever tent you get, make sure the usable interior size is appropriate for
your needs.  My Mountain Pass claims to have a 7'6" floor, but I have to stake
it out tight to get more than about 6'5" which is what I need to sleep without
touching the walls with my head or feet.  Also, make sure you get aluminum
alloy poles, not fiberglass.  Most tents have a bathtub floor where the
waterproof floor wraps up a few inches on the side.  Very nice feature.
Be sure to get a full coverage fly with at least one vestibule.  Two vestibules
(usually with two doors) is even better.  All other things being equal, a
lighter tent is better and will cost more.  But don't trust the manufacturer's
weights; they all lie.

Freestanding tents are easier to setup but tend to weigh more.  They usually
need to be staked for a good pitch.  Non-freestanding tents are lighter but
must be staked out or they won't pitch at all.

Consider the ventilation options, the more the better.  Don't get a four
season tent unless you really will use it in full on winter mountaineering
conditions.  They are heavy and ventilate poorly.  For most winter backpacking
you can sleep right out on the snow.  No bugs to worry about.  Use a tarp for
protection from high winds or heavy snowfall.