For 2013, FAs, at a reasonable salary, who interest me besides WW and Vollmer are:
WRs
Dwayne Bowe
Greg Jennings
DTs
Cliff Avril (so long as his interview is good)
Henry Melton
Ss
Byrd (will cost too much)
Goldson (ditto)
Those are the positions I see targeted by the Pats in FA, too.
WR
I think both Bowe and Jennings will end up being way too expensive with Miami likely bidding for their services. Even Devery Henderson might be looking for more than the Pats would be willing to shell out. Bowe and Jennings probably end up costing nearly as much as just giving Welker his contract. OTOH, thinking in terms of #3/#4 type veterans who might supplant Branch, Domenik Hixon (6'2"/192) could get a look, though. He played for a mere $615k in 2012. And there's always Gaffney, I suppose.
I guess I'm just not seeing any veteran FA WRs out there who impress me who might also be financially reasonable. This might be the year that the Pats grab a couple young, developmental WRs in the draft, instead (and they already appear to maybe have Kamar Aiken and Andre Holmes lined up for Camp).
DT
Avril is a 6'3"/260# DE/DT who played for a Franchise Tag $10.6M in 2012. Aside from the fact that the Pats appear to be covered up with similar guys, what he's likely to command on the open market would be way above what the Pats would likely want to invest. Probably just as well to simply renew Trevor Scott at a reasonable raise.
Melton is great, but Da Bears ain't letting him get away.
Sammie Lee Hill (also DET), Mike DeVito (NYJ), Arthur Jones (Chandler's brother, RFA - BAL) or Vance Walker (ATL) might be more like where the Pats would want to go for veteran depth. Possibly Dorsey, if he's willing to take a significant cut (from $8.77M in 2012, but coming off IR). Even Alan Branch (SEA) might be too dear ($4.55M in 2012). This could also be a position for which the Pats "double-dip" in the draft.
EDIT: I keep forgetting about Desmond Bryant (6'5"/290, OAK, $1.93M in 2012) who FO grades as their top FA Interior DL. BTW, FO's Top Ten FA Interior DL:
<table id="wp-table-reloaded-id-687-no-1" class="wp-table-reloaded wp-table-reloaded-id-687"><tbody><tr class="row-2"><td class="column-1">Desmond Bryant</td><td class="column-2">DI</td><td class="column-3">4</td><td class="column-4">OAK</td><td class="column-5">UFA</td><td class="column-6">+16.5</td><td class="column-7">645</td> </tr><tr class="row-3"> <td class="column-1">Henry Melton</td><td class="column-2">DI</td><td class="column-3">4</td><td class="column-4">CHI</td><td class="column-5">UFA</td><td class="column-6">+15.7</td><td class="column-7">616</td> </tr><tr class="row-4"> <td class="column-1">Mike Devito</td><td class="column-2">DI</td><td class="column-3">6</td><td class="column-4">NYJ</td><td class="column-5">UFA</td><td class="column-6">+11.5</td><td class="column-7">635</td> </tr><tr class="row-5"> <td class="column-1">Richard Seymour</td><td class="column-2">DI</td><td class="column-3">12</td><td class="column-4">OAK</td><td class="column-5">UFA</td><td class="column-6">+9.5</td><td class="column-7">361</td> </tr><tr class="row-6"> <td class="column-1">Vance Walker</td><td class="column-2">DI</td><td class="column-3">4</td><td class="column-4">ATL</td><td class="column-5">UFA</td><td class="column-6">+7.6</td><td class="column-7">539</td> </tr><tr class="row-7"> <td class="column-1">Steve McLendon</td><td class="column-2">DI</td><td class="column-3">3</td><td class="column-4">PIT</td><td class="column-5">RFA</td><td class="column-6">+7.0</td><td class="column-7">139</td> </tr><tr class="row-8"> <td class="column-1">Justin Bannan</td><td class="column-2">DI</td><td class="column-3">11</td><td class="column-4">DEN</td><td class="column-5">UFA</td><td class="column-6">+6.2</td><td class="column-7">542</td> </tr><tr class="row-9"> <td class="column-1">Sammie Hill</td><td class="column-2">DI</td><td class="column-3">4</td><td class="column-4">DET</td><td class="column-5">UFA</td><td class="column-6">+5.6</td><td class="column-7">419</td> </tr><tr class="row-10"> <td class="column-1">Jason Jones</td><td class="column-2">DI</td><td class="column-3">5</td><td class="column-4">SEA</td><td class="column-5">UFA</td><td class="column-6">+5.6</td><td class="column-7">332</td> </tr><tr class="row-11"> <td class="column-1">Aubrayo Franklin</td><td class="column-2">DI</td><td class="column-3">10</td><td class="column-4">SD</td><td class="column-5">UFA</td><td class="column-6">+5.4</td><td class="column-7">285</td></tr></tbody></table>
SS
Agree about Byrd (only got $1.07M in the final year of his rookie deal) and Goldson (who took 1 year in SFO at $6.21M over whatever the Pats offered him for 2012) being way out of reach, financially.
Ed Reed seems likely to retire a Raven at the end of 2013 or 2014.
BTW, another veteran guy I'd consider for SS from the Bills might be George Wilson (6'0"/210) who's going into the final year of his second contract for $4.04M at age 31, but I doubt that even the Bills are stupid enough to screw with him by demanding a restructure for 2013 (which is about the only way he'd be available to the Pats at reasonable money).
There may be a few guys who could sign for relatively cheap as depth, and the Pats could conceivably pick one up for Camp. There might be an aging CB who'd work cheap to convert to safety (ala, Will Allen in 2012 Camp). Again, though, the Pats could be looking to continue their "youth campaign" through the draft on this one, though not necessarily with a 1st or even a 2nd round pick. A guy like Duke Williams (6'1"/200) out of Nevada who has played both CB and FS might be had in the 3rd round.
Anyway, my general feeling is that the Pats won't be making any major FA signings this season, but may be more likely to be filling in around the edges and back-stopping their draft board.