YAY for keeping him RF for as long as possible! There are several options for seats for you. Alot of it depends on your budget. I will list several from most expensive to least expensive! I own a Britax Marathon, an Evenflo Triumph Advance & a Cosco Scenera. They are all good seats. I exspecially LOVE my Marathon & my Triumph. They are both super easy to use & install. If you can afford the Marathon then I would suggest it as it has built in lock-offs that make installing SUPER easy, but if not then my next suggestion would be a Triumph Advance. Good Luck!
Britax Marathon: RF to 33-35lbs (older are 33 & the newer are 35) & FF to 65lbs Can be Tethered while RF!!
These run about $220-$300, depending on the sale. The best option for these is to try one out at like Babies R Us or USA Baby & then buy it online. I bought mine for $220 with no Tax & Free Shipping. Just search Britax Marathon & look untill you find then on sale!
Britax Boulevard: Same stats as above Marathon. The main difference is that this seat has head wings & the Marathon does not. They are also a little more exensive running from $250-$300 depending on the sale. Search for them the same as the Marathon for sales.
Sunshine Kids Radian 65-Skip the 80 unless you need it for a newborn as the 80 will not last you any longer than the 65!: RF to 35lbs & FF to 65lbs. Can be tethered while RF!!
These are GREAT for a 3 accross car seat/booster situation as they are the most narrow on the market! They run about $199+tax. They are usually only found online, although I think USA Baby May carry them, but don't quote me...I am unsure. Usually online is the BEST place for them though! Target.com sells them & you can return to the store.
The 3 Above seats can be tethered with the tether anchor while RF, Britax & Sunshine Kids are the ONLY brand that allow this, do NOT do this with any other brand of seat as it is unsafe to do so!
Evenflo Triumph Advance (Must say Advance in the name): RF to 35lbs & FF to 50lbs.
This is a great seat! Has an infinatly adjusting Harness so no more rethreading the harness to move height ever! This seat runs about $130-$180 depending on the cover you choose & the LATCH anchors it has. The most expensive version has the Alligator LATCH anchors like Britax, I own the LX & LOVE it! Can be bought at Wal-Mart, K-Mart, Babies R Us, Target & Toys R Us!
Safety 1st Uptown: RF to 35lbs & FF to 40lbs. This seat is a good extra seat. It has EPS foam & padding. It has a good decent tall shell. It runs at around $100 & can be bought at Wal-Mart. Although this seat will be outgrown before your child is ready for a booster, so you will need another High Weight Harnessing seat!
Cosco Scenera: RF to 35lbs & FF to 40lbs. This is also a good back up seat. It is a basic no frills, bare bones seat. It does not have alot of padding, but my DS doesn't complain. It runs about $40-$50 at Wal-Mart, Target, & K-Mart. However with this seat make sure that you get the 5 point Harness version as it is safer. Stay away from the one with the Overhead shield or the bar that goes in front. These are Dangerous. This seat will also be outgrown before your child is ready for a booster!
Seats to STAY Away from: Any seat that says All In One, 3 in 1 or that it will be the last seat you ever need. They are outgrown WAY to early & are not ERF friendly as it has a short shell. My son outgrew the All In One I owned at 18 months completely. Also stay away from the Comfort Sport. It is not ERF friendy as it has a short shell. The straps are also notrious for getting twisted & staying that way. The Titan Elite, short shell & twisty straps. Any seat with an overhead sheild. Also most seats with a 40lb harness weight limit.